February 18, 2022



One of the cool things about our hobby is that we can switch stuff up.

For months, I've been kicking around ideas for my next new aquarium. Well, for a new concept within one of the existing aquariums I have. It gets stronger every day. And it's a normal sort of thing...At least, I tell myself that it is!

I mean, we all do this...like, constantly, right? Edit. Ideate. Iterate. 


It's not a bad idea to evolve existing tanks.

Sometimes, it's a little "adjustment" to an existing system.

Incremental changes or aesthetic tweaks that get you into a different "groove."

Other times, you get the call in your mind to just "erase" and start fresh. Sometimes, it's for specific reasons: the current setup isn't working well for you or your fishes. It's tough to maintain, or difficult to keep up with.

Or maybe, just maybe- you're a bit "over" it.

You know, ready for something totally new.

Those of us who are limited in the number of aquariums that they have (or want to have, as in my case!) are often faced with a dilemma of sorts: We want to try different things, and the only way to do it... is to break apart one of the current aquariums that we have going, and to re-do it.

That kind of sucks...but in a way, this sort of compromise is part of being a hobbyist, right? 

Tinkering. Tweaking. "Playing" with stuff.  


You can call it something fancy, like "iterating"- but in the end, it's really about tearing up your current aquarium and re-doing it in some different way.

And that's just part of the game, right?

Not everyone can have 30, 12, or even 4 aquariums in their home, shitty though that might be! Yet, many of us have big ideas, unique plans, and strong aspirations...lots of 'em- and the only way to execute is to do these "makeovers" on a regular basis...

Or at least, when the "muse" hits!

I don't know about you, but it's always been a bit of a "guilt-inducer" for me to do that. I mean, you've got this aquarium that is (hopefully) all that you expected it would be. Looks great, functions awesomely, and has been perfectly manageable. And then, in the middle of this wonderful endeavor, you have the urge- or perhaps the inspiration- to try something totally different. 

And you break out the metaphorical "eraser" and just wipe the slate clean; start fresh. 


It was never easy for me to do this.

I mean, I'm the guy that would keep tanks set up for years with only minor aesthetic/fish population tweaks along the way. Patient. Stable. Consistent.

I was always kind of proud of that.



I used to think that it was kind of weird how those competitive aquascaper people who you see on Instagram and YouTube could just tear down an amazing tank and start all over after just a few months, seemingly without a care in the world.

How could they just do that?

And then, the ideas came.

As the owner of what people tell me has become a sort of niche-centric, progressive, creativity-enabling/inspiring company, I realized that I needed to show some different "looks" that I myself, or my colleagues have done- on a semi-regular basis...to sort of "keep it real" for me and to inspire our customers. Perhaps it can be seen as an excuse of sorts, but there is some legit rationale behind it!

I mean, I receive lots and lots of pics from talented hobbyists worldwide each week, showing their amazing botanical-method aquarium work- but it is also important to show my own stuff. It keeps me in touch with the "craft"; the reality of what we do. And let's face it- it's more authentic when you're a "doer"- not just a "talker."


And still, for a long time- I'd wonder just how these competition 'scapers could pull this off (at least mentally)- re-doing tanks so frequently. I mean, they have the talent...It's the mindset that eludes me.

What is it?


And then I began to understand: It's about this need to "continue."

An urge to create, expand horizons...

And when you're space-limited (or, "tank-limited") the only way forward is to break down the current tank and start working your new idea.

I've finally gotten myself to that place after decades...

It becomes more of a process...Or maybe, a progression of sorts.

And after psyching myself up...the day comes, and I dive right in.

Out go the fishes, re-housed to a different tank (if keeping different fishes is part of the plan, that is), and the "remodeling" process happens.

And, for about the first hour, I usually feel guilty that I broke apart something cool. Something really nice. Special, even. I worry about the well-being of the animals, fist and foremost...but only for a little bit, because I know that wherever I house them, it will be in optimum conditions for them...('cause that's how I roll!)

So, then the guilt gives way to a tinge of nostalgia...Remembering how nice it was to take the tank from idea on a piece of paper to full-fledged miniature ecosystem. I recall the challenges, obstacles, and triumphs...

Deep breaths.

Within two hours, I'm back to being excited again, staring at a now empty tank- you know, the proverbial "blank canvas" that we all drool over. Aquarists love this sort of stuff! We LIVE for it! At that point, it's all about the possibilities. The chance to do something really special "this time."

Can you relate to this process? This mindset? I suppose if you have 45 tanks in your basement, this manifests itself differently, but to those of us with a handful- or less- the process takes on a far more "sacred", almost ritualistic meaning.

Yet, we do it.

We plunge forward. And we realize that the best part of being an aquarium hobbyist...is being an aquarium hobbyist. Regardless of what we're doing at any given moment.

I mean, if you're satisfied with the tank you've got the way it is- mazeltov! Good for you. If you're not...or if you just feel the urge to do something different...Do it.

Don't feel guilty like I do sometimes. Feel excited. Motivated. Stoked.

Know that you're at another fork in the road on your aquatic journey. And it's totally okay to go in whatever direction you want.

And that's pretty damn cool, if you ask me.

I hope that the story of my little epiphany about this subject has struck a chord within you.

Keep moving forward...push the outside of the envelope. Run down that dream. Scratch the itch.

Stay forward-thinking. Stay creative. Stay relentless. Stay engaged...


February 15, 2022


Function, form, and the call of "microhabitats" and niches...

One of the most nitrating things about our era of aquarium keeping is that we have access to an enormous amount of information about the wild habitats of our fishes. If you make the effort, you can find scientific research papers on just about any fish, locale, and habitat you can think of. With all of this information available, the sheer number of habitats which you can replicate in an aquarium is mind boggling!

And it's not just habitats, per se- it's little ecological niches within the habitats- known to ecologists as "microhabitats" -defined  as habitats which are small or limited in their extent, and which differ in character from some surrounding more extensive habitat.

These can be both compelling and rewarding to use as an aquarium subject! And, not surprisingly, these may encompass simple materials which we as botanical-method aquarium enthusiasts are quite familiar with! In many natural aquatic habitats, fallen tree branches, twigs, and leaves, form a valuable and important part of the ecosystem. 

The complexity and additional "microhabitats" they create are very useful for protecting baby fishes, breeding Apistogramma, maintaining Poecilocharaxcatfishes, Dicosssus, and other small, shy fishes which are common in these locales. They provide foraging areas, as well as locations to sequester detritus, sediments, and nutrients for the benefit of the surrounding ecosystems.

It would be remarkably easy- and interesting- to replicate these habitats within the confines of the aquarium. The mind-blowing diversity of Nature is comprised of millions of these little "scenes", all of which are the result of various factors coming together.

As aquarists, observing, studying, and understanding the specifics of microhabitats is a fascinating and compelling part of the hobby, because it can give us inspiration to replicate the form and more important- the function-  of them in our tanks!

We spend a lot of time discussing and considering the various components and interactions of water and terrestrial habitats, and I think that if WE haven't made a compelling case, our Nature will!

Consider the "karsts..."

A karst is an area of land made up of limestone. Limestone, also known as chalk or calcium carbonate, is a soft rock that dissolves in water. This process produces geological features like ridges, towers, fissures, sinkholes and other characteristic landforms. Many of the world’s largest caves and underground rivers are located in karstlands.

(Karstic terrain. Image by Jan Nyssen used under CC BY-SA 4.0)

The porous limestone rock holds a lot of groundwater, ponds, and streams, sometimes located underground. And those cool  structures known as cenotes (closed basins)! Yeah, we'll revisit those some other time.

Karsts are characterised by the presence of caves, sink holes, dry valleys and "disappearing" streams. These landscapes are known for their groundwater flow and efficient drainage of surface water through a wide network of subterranean conduits, fractures and caves.

Karst are found throughout the world, including France, China, the Yucatán Peninsula; South America, and parts of the United States.

In typical karstic habitats, the water is very clear, becoming turbid after heavy rains. Flash floods occur several times during the rainy season. In this period the stream width increases, making available habitats to be colonized, called  "temporary stretches".

Are you thinking what I'm thinking? Yeah, these could be interesting aquarium subjects! 

Yeah. And since a bunch of 'em occur in South America, where some of our fave fishes come from...this could be really interesting!

A fascinating neotropical karst landscape is located in the São Francisco River basin, Minas Gerais State, in Brazil. The fish diversity in these waters is significant. One study that I stumbled upon identified 28 species distributed in 3 orders and 9 families in this one locale alone!

The pH values in the South American karst habitats I found studies on range from 6.3 to 8.2, and averaged around 7.2 (slightly alkaline). Water temperatures average around 75 degrees F ( 23.8C), conductivity averages .30mS/cm, and the ORP averages 178 mv. (lower than one might expect, right? In reef keeping, we shoot for around 300 mv, so...) It's thought that the low levels of ORP can be associated with environmental pollution and/or high concentrations of ions, which is consistent in waters with karstic origins.

From an aquarist's perspective, karstic habitats should be pretty easy to replicate in the aquarium, right? Lots of smooth stone and sand, with a scattering of leaves and a few branches. This is one instance where I'd tell you to use plenty of activated carbon or other chemical media, to keep the water more or less clear. I mean, in some locales, as we mentioned previously, it's crystal clear!

Lots of epiphytic algal growth, some broken up leaves, aggregations of rocks...sand...I mean, this is like aquarist paradise! You can pretty much use every trick in the book and still come up with a reasonably faithful biopic representation- functionally aesthetic, no less! And, for some of you, not to have to deal with super acidic water and dark tint could be a real win, huh?


This is the most cursory description of karsts- but I hope it whets your appetite to learn more about them! Dig deeper, and you'll find a remarkable amount of information about them.

And of course, I can't just discuss one interesting habitat without mentioning another, right? 

Among the richest habitats for fishes in streams and rivers are so-called "drop-offs", in which the bottom contour takes a significant plunge and increase in depth. These are often caused by current over time, or even the accumulation of rocks and fallen trees, which "dam up" the stream a bit. (extra- you see this in Rift Lakes in Africa, too...right? Yeah.) 

Fishes are often found in drop offs in significant numbers, because these spots afford depth (which thwarts the hunting efforts those pesky birds), typically slower water movement, numerous "nooks and crannies" in which to forage, hide, or spawn, and a more restive "dining area" for fishes without strong currents. They are typically found near the base of tree roots...From an aquascaping perspective, replicating this aspect of the underwater habitat gives you a lot of cool opportunities.

And of course, these types of habitats are perfect subjects for aquarium representation, aren't they?

If you're saddled with one of those seemingly ridiculously deep tanks, a drop-off could be a perfect subject to replicate. And there are even commercially-made "drop-off" tanks now! Consider how a drop-off style encompasses a couple of different possible niches in the aquarium as it does in Nature!

Overhanging trees and other forms of vegetation are common in jungle/forest areas, as we've discussed many times. Fishes will tend to congregate under these plants for the dimmer lighting, "thermal protection", and food (insects and fruits/seeds) that fall off the trees and shrubs into the water. (allochthonous input- we've talked about that before a few times here!) And of course, if you're talking about a "leaf litter" or botanically-influenced aquascape, a rather dimly-lit, shallow tank could work out well.

And of course, in the areas prone to seasonal inundation, you'll often see trees and shrubs partially submerged, or with their branch or root structures projecting into the water. Imagine replicating THIS look in an aquarium. Contemplate the behavioral aspects in your fishes that such a feature will foster!

Lots of leaves, small pieces of wood, and seed pods on the substrtae- doing what they do- breaking down-would complete a cool look. For a cool overall scene, you could introduce some riparian plants to simulate the bank as well. A rich habitat with a LOT of opportunities for the creative 'scaper!

Why not create an analogous stream/river feature that is known as an "undercut?" Pretty much the perfecthiding spot for fishes in a stream or river, and undercuts occur where the currents have cut a little cave-like hole in the rock or substrate material near the shore.

Not only does this feature provide protection from birds and other above-water predators, it gives fishes "express access" to deeper water for feeding and escaping in-water predators!

Trees growing nearby add to the attractiveness of an undercut for a fish (for reasons we just talked about), so subdued lighting would be cool here. You can build up a significant undercut with lots of substrate, rocks, and some wood. Sure, you'd have some reduced water capacity, but the effect could be really cool.

Yeah, I could go on and on with all sorts of ideas about how to recreate all sorts of microhabitats in the aquarium- because there are a seemingly limitless number of them to explore and replicate! 

There is a reason why all of these unique environments are successful, and why life exists- and indeed- thrives- in them. And there are reasons why we're starting to see incredible results when replicating some of the functional aspects of these environments in a more faithful manner than may have been attempted before.

And we have all of the "tools" that we need to do this:

Patience. A long-term view. Information. Observation. Understanding.  

You've got this.

Stay creative. Stay enthusiastic. Stay observant. Stay patient. Stay excited...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

February 10, 2022


Random, or not?

I'm a big fan of some of the aquatic features that you see in Nature. The seemingly random, unusual, and almost "disorderly" appearance of many aquatic features is really inspiring. I mean, Nature takes all of these random elements, and combines them in amazing ways.

And when you consider that virtually all freshwater fishes come into contact with some botanical materials throughout their existence, it opens your mind to the possibilities. In virtually every body of water, you'll find some sunken branches, tree trunks, leaves, roots, seed pods, etc.- stuff which can create really interesting features to support all sorts of fishes.

And this doesn't require us to do tremendous amount of "aquascaping" in the traditional hobby sense. Rather, it's more about seeing how Nature does it...


Think about this: We as hobbyists spend an enormous amount of energy and effort creating meticulous wood arrangements and rockwork in our aquariums, trying to achieve some sort of perfectly-radioed, artistic layout.

Personally, I'd like to see us apply the same level of dedication to really understanding and replicating the "function" of Nature in relation to its appearance, and embracing the random nature of its structure in our tanks.

When you look at those amazing pictures of the natural aquatic habitats we love so much, you're literally bombarded with the "imperfection" and randomness that is nature. Yet, in all of the "clutter" of an igarape flooded forest, for example, there is a quiet "elegance" to it.

There is a sense that everything is there for a reason- and not simply because it looks good. It IS perfect. Can't we bring this sense to our aquariums? I think we can...simply by meeting nature halfway.

Is there not also beauty in "randomness", despite our near-obsessive pursuit of rules, such as "golden ratio", color aggregating, etc? Just because last year's big 'scaping contest winner had the "perfect" orientation, ratios, and alignment of the (insert this year's trendiest wood here) branch within the tank, doesn't mean it's a real representation of Nature, let alone, the natural functionality of "randomness." 

In other words, just because it looks good, it doesn't mean it's what Nature looks like. That's perfectly okay, of course, except when you're blabbing on and on about how your tank is a "beautiful recreation of Nature", as hobbyists tend to do online!

I think it's perfectly okay for hobbyists to simply say that they have created a beautiful, artistic, nature-inspired arrangement in their tanks! A beautiful tank is a beautiful tank- regardless of how you label it. It's that misappropriation of the term "Nature" or "Natural" that drives me crazy.

There's a disconnect, of sorts- and I think it starts with our collective failure as hobbyists to take into account how materials like branches, leaves, twigs, and seed pods arrive in their positions within an aquatic habitat. These factors have a huge influence on the way these habitats form and function.

When you think about how materials "get around" in the wild aquatic habitats, there are a few factors which influence both the accumulation and distribution of them. In many topical streams, the water depth and intensity of the flow changes during periods of rain and runoff, creating significant re-distribution of the materials which accumulate on the bottom, such as branches, leaves, seed pods, and the like.

Larger, more "hefty" materials, such as submerged logs, etc., will tend to move less frequently, and in many instances, they'll remain stationary, providing a physical diversion for water as substrate materials accumulate around them.

Most of the smaller materials, like branches, seed pods, and leaves may tend to move around quite a bit before ultimately settling and accumulating in a specific area-perhaps one with less flow, natural barriers like branches or fallen trees, a different bottom "topography", and other structural aspects, like bends and riffles.

Sometimes, seasonal flooding or overflowing streams run through previously terrestrial habitats, with the water moving materials around considerably. One might say that the "material changes" to the environments created by this movement of materials can have significant implications for fishes. In the wild, they follow the food, often existing in, and subsisting off of what they can find in these areas.

Yeah...They tend to be attracted to areas where food supplies are relatively abundant, requiring little expenditure of energy in order to satisfy their nutritional needs. Insects, crustaceans, and yeah- tiny fishes- tend to congregate and live around floating plants, masses of algae, and fallen botanical items (seed pods, leaves, etc.), so it's only natural that our subject fishes would be attracted to these areas...I mean, who wouldn't want to have easy access to the "buffet line", right?

Right there, you can see that there is some predictability and utility in the "random" nature of aquatic habitats. They provide enormous support for life forms at many levels. 

Any random stream in Nature contains inspiration and ideas which we can apply to our aquascapes, without having to overthink it. Sure, even the simple act of placing a piece of wood in our tanks requires someconsideration...

However, it think a lot of it boils down to what we are placing the emphasis on as aquarists. Perhaps it's less about perfect placement of materials for artistic purposes, and more about placing materials to facilitate more natural function and interactions between fishes and their environment.

We make those "mental shifts" and accept the dark water, the accumulation of leaves and botanicals, the apparent "randomness" of their presence. We study the natural habitats from which they come, not just for the way they look- but for WHY they look that way, and for how the impacts of the surrounding environments influence them in multiple ways.

It goes beyond just finding that perfect-looking branch or bunch of leaves to capture a "look." We've already got that down. We can go further...

Sure, embracing some different aesthetics can seem a bit- well, intimidating at first, but if you force yourself beyond just the basic hobby-oriented mindset out there on these topics, there is a whole world of stuff you can experience and learn about!

And the information you can gain from this process just might have an amazing impact on your aquarium practice; that might just lead to some remarkable breakthroughs that will forever change the hobby!

There is a tremendous amount of academic material out there for those willing to "deep dive" into this. And a tremendous amount to unravel and apply to our aquarium practices! We're literally just scratching the surface. We're making the shifts to accept the true randomness of Nature as it is.  We are establishing and nurturing the art of "functional aesthetics."

I suppose that there are occasional smirks and giggles from some corners of the hobby when they initially see our tanks, with some thinking, "Really? They toss in a few leaves and they think that the resulting sloppiness is "natural", or some evolved aquascaping technique or something?"

Funny thing is that, in reality, it IS a sort of evolution, isn't it?

I mean, sure, on the surface, this doesn't seem like much: "Toss botanical materials in aquariums. See what happens." It's not like no one ever did this before. And to make it seem more complicated than it is- to develop or quantify "technique" for it (a true act of human nature, I suppose) is probably a bit humorous. 

On the other hand, most of us already know that it's not just to create a cool-looking tank. It's not purely about aesthetics. The aesthetics are a "by-product" of the function we push for. And, another thing We don't embrace the  dark, often turbid water, substrates covered in decomposing leaves and twigs, and the appearance of biofilms and fungal growths on driftwood because it allows us to be more "relaxed" in the care of our tanks, or because we think we're so much smarter than the underwater-diorama-loving, hype-mongering competition aquascaping crowd.

Well, maybe we are? 😆

Look, we are doing this for a reason: To create more authentic-looking, natural-functioning aquatic displays for our fishes. To understand and acknowledge  that our fishes and their very existence is influenced by the habitats in which they have evolved. 

Wild tropical aquatic habitats are influenced greatly by the surrounding geography, flora, and weather of their region, which in turn, have considerable influence upon the population of fishes which inhabit them, and their life cycle. It may appear to be a completely random process, but the reality is that it's surprisingly predictable, often tied into seasonal flood pulses and meteorological cycles.

It's something that we can recreate, to a certain extent- in our aquariums.

And, think about this: When we add botanical materials to an aquarium and accept what occurs as a result-regardless of wether our intent is just to create a different aesthetic, or perhaps something more- we are to a very real extent replicating  the processes and influences that occur in wild aquatic habitats in Nature.

The presence of terrestrial botanical materials such as leaves, seed pods, and twigs in these aquatic habitats is fundamental to both these wild aquatic habitats, and to the aquariums we create to replicate them.



An aquarium is not just a glass or plastic box filled with water, sand, plants, wood, leaves, seed pods, and fishes.

It's not just a disconnected, clinical, static display containing a collection of aquatic materials.

It's a microcosm.

A vibrant, dynamic, interconnected ecosystem, influenced by the materials and life forms-seen and unseen- within it, as well as the external influences which surround it. 

An aquarium features, life, death, and everything in between.

It pulses with the cycle of life, beholden only to the rules of Nature, and perhaps, to us- the human caretakers who created it.

But mainly, to Nature.

The processes of life which occur within the microcosm we create are indifferent to our desires, our plans, or our aspirations for it. Sure, as humans, we can influence the processes which occur within the aquarium- but the outcome- the result- is based solely upon Nature's response.

In the botanical-method aquarium, we embrace the randomness and unusual aesthetic which submerged terrestrial materials impart to the aquatic environment. We often do our best to establish a sense of order, proportion, and design, but the reality is that Nature, in Her infinite wisdom borne of eons of existence, takes control.

We have two choices: We can resist Nature's advances, attempt to circumvent or thwart her processes, such as decomposition, growth, or evolution.

Or, we can scrape away "unsightly" fungal growth and biocover on rocks and wood, remove detritus, algae, replace our leaves, and trim our plants to look neat and orderly.

Or, we can embrace Her seemingly random, relentless march, and reap the benefits of Her wisdom.

Stay thoughtful. Stay resourceful. Stay curious. Stay observant. Stay diligent...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


February 08, 2022


Just...maintain! A little review on the maintenance of botanical-method aquariums.

One of the more common questions we receive here at Tannin, and via our social media accounts, is, "How do you maintain one of these (botanical method) aquariums?"

It really is a great question, because, although we've talked about it quite a bit over the last several years, it's a very fundamental item which we haven't talked about in detail recently... So, why not revisit it today?


As we've talked about before, for the longest time, there seemed to have been a perception among the mainstream aquarium hobby that tanks with lots of botanical materials were delicate, tricky-to-maintain systems, fraught with potential disaster; a soft-water, acidic environment which could slip precipitously into some sort of environmental "free fall" without warning. And there was the matter of that "dark brown water..."

And the aquairum hobby has, for decades, equated brown water with "dirty", "dangerous", and "non-sustainable..."

Perceptions which require a bit of examination and understanding of before we can successfully navigate the world of botanical method aquairums. 

Yeah, like so many things in our little hobby speciality, it's a matter of understanding exactly what you're getting into. I think that the most difficult aspect of a botanical method aquarium is to understand exactly what it is, why it's set up the way it is, and how it actually works. The fundamentals are everything here. 

So, how do we keep these aquariums running for extended periods of time? Through continuous, regular maintenance, of course! Let's talk about some of the "best practices" that we engage in to keep these tanks running and looking their best.

It starts with the way you set up your botanical method aquarium, and how it relies on natural processes to function.


If you're "converting" an existing aquarium, start slowly, gradually building up your quantities of botanical materials over a period of weeks, or even months, until you reach a level that you like aesthetically, and which provides the type of manageable environmental parameters you and your fishes are comfortable with. This is essential, because how we start our aquariums dictates how they will run over the longer term.

And of course, you'll need to understand the progression of things that happen as your tank establishes itself. And, perhaps most important, you'll need to make some mental "adjustments" to accept and appreciate this different function and aesthetic.

Also, you'll have to get used to a certain amount of material breaking down in your tank. It's natural, and part of the function... and the aesthetic. Accepting the fact that you'll see biofilms, fungal growth, detritus, and even some algae in your system is something that many aquarists have a difficult time with. As we've discussed numerous times here, it goes against our "aesthetic upbringing" with regards to what an "attractive, healthy-looking tank" is! 

We have learned to understand and appreciate this stuff, and that accepting these things is not an excuse to develop or accept lax maintenance practices! It's understanding that this is part of the normal function of Nature. It's a "call to awareness" that there is probably nothing wrong with your system when you see this stuff. It's quite contrary to the way we've been "trained" to evaluate the aesthetics of a typical aquarium.

Okay, let's talk aesthetics, one more time...Watch some underwater videos and study photos of environments such as the Amazonian region, etc., and you'll see that your tank is a much closer aesthetic approximation of Nature than almost any other type of system you've worked with before, in both form and function.

This is a significant thing, really!

And, to your comfort, you'll find that botanical method aquariums are as stable as any other if you follow regular maintenance and good old common sense.

So, what are we talking about, in regards to regular maintenance?

Well, for one thing, water exchanges. Because the topic is so well discussed in the aquarium world,  I'll keep it relatively brief on this topic: 

What’s a good water-exchanging regimen?

I’d love to see you employ 10% per week...It’s what I’ve done for decades, and it’s served me- and my animals- very well! Regardless of how frequently you exchange your water, or how much of it you exchange- just do them consistently. And of course, as previously discussed, don't go crazy siphoning every bit of detritus out during the process.

Remember, that in an aquarium which encourages the growth of bacteria, fungi, copepods, etc., the organic material contained in detritus becomes part of the "food web." And everybody up the food chain can benefit from the stuff.

So, by going "full ham" and siphoning every last speck of detritus in your tank, you're essentially breaking this chain, and denying organisms at multiple levels the chance to benefit from it! Yeah, over-zealously siphoning this material from your tank effectively destroys an established community of microorganisms which serve to maintain high water quality in the closed environment of an aquarium!

This is a super-important point to remember!

In an ironic twist, I believe that it's far more common for those "anomalous" ammonia spikes and such that aquarists report periodically, to  have their origin in over-zealous cleaning of aquariums and filter media, as opposed to the accumulation of detritus itself. So, yeah-taking out all of the "fish shit" is actually removing a complex microbiome that's keeping your tank healthy!

Even something as seemingly "mundane" as the way we maintain our botanical-method aquariums requires us to make some "mental shifts" to appreciate our methodology more thoroughly, doesn't it?

Now, during water exchanges, it's almost inevitable that some stuff gets shifted around. Leaves and seed pods are pretty lightweight materials, and as they decompose, they're even more lightweight and "mobile."

And that's not necessarily a bad thing. Don't get stressed if you stir some stuff up. Your tank will be fine.

Think about the natural leaf litter beds, and the processes which influence their composition, structure and resilience. Many litter beds are long-term "static" features in their natural habitats. Almost like reefs in the ocean, actually. Yet, there is a fair amount of material being shifted around constantly by current, rain, flooding, and the activities of fishes.

Yeah, stuff does get disturbed and redistributed.

The organisms which reside in these systems deal with these dynamics effectively. They have for eons.

The benthic microfauna which our fishes tend to feed on also are affected by this phenomenon, and as mentioned above, the fishes tend to "follow the food", making this a case of the fishes learning (?) to adapt to a changing environment.

And perhaps...maybe...the idea of fishes sort of having to constantly adjust to a changing physical (note I didn't say "chemical") environment could be some sort of "trigger", hidden deep in their genetic code, that perhaps stimulates overall health, immunity or spawning?

Something in their "programing" that says, "You're at home...the season has changed, because there's an influx of new water...leaves are rolling around..." Perhaps not as "specific", but something like that, which can trigger specific adaptive behaviors?

I find this possibility fascinating, because we can learn more about our fishes' behaviors, and create really interesting habitats for them, simply by adding botanicals to our aquariums and allowing them to "do their own thing"- to break apart as they decompose, move about as we change water or conduct maintenance activities, or to be added to from time to time.

Well, I mentioned the whole "breaking down" part about botanicals here, so I should say a little about that. 

As we have discussed for years, botanical materials break down and start decomposing as soon as they are added to your aquarium. It's normal. It's natural. It's to be expected.  Some materials, like the harder seed pods, last a very long time- almost indefinitely- before they finally are broken down by biological activity. Other stuff, like softer seed pods and leaves, tend to break down much more quickly.

Yeah, leaves should be considered the most "temporary" or ephemeral items we utilizing in our botanical method tanks, requiring replacement regularly. Those seed pods and stems tend to last longer and it's personal preference to leave them in, or remove as desired.  

So, DO you remove the botanical materials from your aquarium as they break down? 

For reasons I've touched on numerous time here in "The Tint", I personally like to leave all of these materials in the aquarium until they completely break down, which I believe facilitates the very ecological processes which help the ecosystem of our aquariums run. And, leaving the material "in situ" while it breaks down does NOT "pollute" the aquarium, if it's otherwise well managed (ie; if you conduct regular water exchanges, filter media replacements, feed carefully, and stock sensibly, etc.). 

I think that we need to look beyond the simple "aesthetic" of the leaves and other botanicals in our tanks, and consider them more than just hardscape "props." Rather, they are functional materials, which perform biological, environmental, and physical/structural roles in the aquarium- just as they do in Nature.

The same processes and functions which govern what happens to these materials in the wild occur in our aquariums. And, if we reject our initial instinct to "edit" what Nature does, the aquarium takes on a look and vibrancy that only She can create. It's that simple. "For best results, don't fuck with it!"

I wouldn't get too carried away with trying to remove any of it, really.

Remember, most of this "stuff"- the broken-down botanical and the resulting detritus and such- is utilized by organisms throughout the food chain in your tank...and as such, is a "fuel" for the biological processes we are so interested in.

No sense disrupting them, right?

What goes down...doesn't always have to come up.

Take care of your tank by taking care of the enormous microcosm which supports its form and function. And that means, not removing all of this material as it decomposes. I know, I've said it several times already in this one piece, and countless times in "The Tint" and elsewhere, but it's really a fundamental part of the botanical method of aquarium keeping.

One physical maintenance task that I have found to be continuous and necessary is the cleaning of filter intakes, mechanical filter media, and water pumps. With a constantly-decomposing array of botanical materials streaming into the water column, lots of small debris tend to get sucked into filter intakes, pumps, and of course, mechanical filter media. These need to be cleaned/replaced on a regular basis; perhaps even more frequently than other maintenance tasks.

It's simply part of the game when working with a botanical-method aquarium!


There are other "tricks" to maintaining environmental consistency in botanical method aquariums, which we can re-visit in future installments. The bottom line here, though, is that these aquariums are no more difficult to maintain than any other type of system we work with in the hobby. They simply require a basic understanding of ecological/biological processes, and how they play out in our tanks. It requires patience, consistency, and execution- attributes which are ideal for any hobbyist to possess.

Our idea of what a beautiful, healthy aquarium is may vary substantially from the "mainstream" aesthetically- but you won't be able to make that argument from a functional perspective when you employ common, well-known aquarium maintenance practices. 

Just remember that the long term success of botanical method aquariums requires a mix of knowledge and action...nothing all that different from what you've already come to understand in the aquarium hobby.

Just..maintain. Literally! 

Stay persistent. Stay observant. Stay curious. Stay thoughtful. Stay patient...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

February 04, 2022


Transitioning a botanical method aquarium: A Case Study

One of the best things about a botanical-method aquairum is that it is a dynamic, evolving, and, well "flexible" environment to work with. By its very nature, the botanical-method aquarium changes- and can be changed- with relatively little effort on our part, while still embracing natural processes.

Case in point has been the little tank we've featured recently- a deliberate attempt to highlight this "pivotable" nature of botanical method aquariums. It started life as one of our "classic" configurations- a leaf litter habitat. A simple aquarium, which consists of a sprinkling of sand, a bunch of leaves, and a few twigs.

Botanical method aquarium-keeping at its most simple and elegant.

As you know, we've done a number of aquariums like this over the years, and they have been among our favorites. They're easy to create, really easy to manage, and teach you almost everything you need to know about running a botanical-method aquarium. You will learn about preparation of the materials, how they interact with water, and what life forms colonize them (ie; biofilms and fungal growths).


This configuration is a perfect "testbed" for the idea that botanical method aquariums can generate their own supplemental food sources for their inhabitants, if allowed to develop undisturbed for a while. 

It's also a great "foundation" for other experiments with botanical method aquariums, as we'll discuss shortly. 

One of the things that I love the most about this approach is that you can use such a small variety of materials, yet achieve a dramatic, ecologically rich aquarium with ease. The most important task is to prepare the leaves in order for them to sink and be able to recruit biofilms and fungal growths quickly, and ultimately decompose. 

Then, it's really a matter of simply waiting for the "bloom" of biological activity. You also have the option of "inoculating" your tank with bacterial supplements or cultures of microorganisms, like Paramecium, etc., as well as copepods or organisms like Daphnia or Cyclops. These are fun little experiments that can really help you create a functional little ecosystem from the outset, and help provide some supplemental food sources for your fishes when they're added.


The idea couldn't be more simple. The execution is really easy. The environmental evolution which arises couldn't be more interesting! Yeah, easy. In fact, it was really a matter of setting in the leaves and twigs, and...doing nothing. Fungal growths form. Biofilms are recruited. Leaves soften and ultimately decompose...Stuff that will happen without any real intervention on your part...

This is really easy.



From an aesthetic perspective, this type of aquarium, by virtue of the fact that it uses a large amount of botanical materials, achieves a sort of "established" look very quickly. And from a functional standpoint, I find that these "leaf-litter-centric" systems seem to "settle down" and stabilize rather quickly, too. Very little fluctuation in the water parameters seems to occur after the initial setup, if lthey're eft undisturbed.


I could have managed this tank much like I had managed leaf litter systems in the past...Indefinitely letting it evolve, occasionally topping off with new leaves. Making few, if any changes of any kind.

Yet, that was not the destiny I had in mind for this tank. 

The idea behind this tank was to demonstrate that you could create a heavily botanically-influenced aquarium, yet "transition" if you want, and easily keep and grow aquatic plants in the system as well. The "transitional" part was when I added aquatic plants. 

Taking this aquarium from a "hardscape" ( to steal an aquascaping term) to a "quasi-biotopic" planted aquarium was a fun! I envisioned a section of a Southeast Asian stream, where the epiphytic Microsorum is growing on some submerged twigs and branches near the shoreline.

I've seen videos of this feature a few times, and was always taken by the extremely luxurious growth of Java Fern right over and into a section of terrestrial material. The dark water, lighter colored sand, and mass of decomposing leaves and branches made this too irresistible to overlook!


Once again, the interplay of the terrestrial and the aquatic habitats is incredible and alluring to me. And, since there was little substrate in this tank, keeping regionally appropriate rooted plants, like Cryptocoryne, was not possible from the outset. The epiphytic nature of Java Fern made it a perfect plant for this tank!

The idea wasn't just to place a few specimens of Microsorum here and there on the wood. Rather, it was to pack it heavily with them, creating a lush, overgrown look immediately. I'd rather be in the position of having to thin out and prune a slow-growing plant in a few weeks than be waiting for a few specimens of said slow-growing plant to cover a large surface area!

(See- I can be impatient!)


The idea of a dark, earthy, yet lushly planted aquarium has always appealed to me. Yeah, even though I'm not known for my use of plants in my work, I have been a fan of this "jungle"-type of approach to aquatic plants for many years. Interestingly, when I peruse images of the "Nature Aquarium" style aquairums, it's always the more lush, almost "overgrown"-looking tanks that catch my eye.

I am a firm believer in Takashi Amano's embrace of  the Japanese philosophy of "Wabi-Sabi"- an acceptance of the transient nature of things, and their natural imperfections. And the approach I took with this tank- creating an evolving, semi-ephemeral "hardscape" of leaves and twigs, utilizing a significant quantity of just one species of plant, and allowing it to grow extensively in the tank, is as close to wabi-sabi as you'll ever see me deliberately come! 

Now, one thing I did was to "corral" most of the leaf litter into and among the matrix of branches. I did this because I wanted to see some exposed substrate for contrast, and wanted to emulate and emphasize the way leaf litter accumulates among submerged roots in Nature.

The inhabitants had to be  a species of Rasbora, (R. hengeli) and one of my long-coveted fishes, Vaillant's Chocolate Gourami", Sphaerichthys vaillanti. This fish is an idea candidate for such a tank. Not only is the tank reasonably small, so I could actually see this shy fish now and again- it has deeply tinted water, and is further darkened with the thick matrix of branches and dense aquatic vegetation- a perfect representation of their wild habitat!


I really want to impress upon you how easy this aquairum is to equip, set up, run, and manage.  You could easily get by with less "gear" than I used.

Let's do a quick "recap" of the materials used for this setup:


Aquarium: Ultum Nature Systems "60S" (23.62'x14.17"x7.09")- 10 U.S. Gallons

Filter: Aqueon "Quietflow AT10" Internal Filter 

Heater: Finnex "HMX 50S" 50-watt submersible
Surface Skimmer: Ehiem "Skim 350"
Lighting: Room Ambient, supplemented with an LED floor lamp I purchased on Amazon



Substrate: CaribSea "Sunset Gold" sand, Tannin NatureBase "Varzea" sedimented substrate (Substrate materials were mixed together to create a substrate layer approximately 1/4"-1/2" inch (.635- 1.27cm) deep ).

Live Oak Leaf Litter

Large Oak Twigs

A few pieces of Borneo Catappa Bark

Java Fern "Narrow Mini"

And that's it...

Now, these are the things that I used...You can certainly set up similar tank utilizing different equipment and materials. A lot of hobbyists would have used a canister filter, which I've done in the past. However, as you know, I pretty much despise all cannister filters for reasons I can't always quite articulate, so I opted for the small internal filter. And you don't have to use a surface skimmer, but I hate surface film, so in non-overflow-equipped tanks, it's a "necessary evil" for me.

Yes, the equipment is visible unless you go to some lengths to hide it (part of the reason why everyone loves canisters!), but my "upside" is that I don't have to deal with that damn "glassware" (one of the most awful, shortsighted inventions in the history of aquarium keeping, IMHO. Absolutely stupid, overpriced, fragile, and shitty, in case you had doubts as to my position about glassware! 😆).

Deep breath, Scott...

So, it was sort of a "lesser of two evils" thing for me!

Personally, if a decent "all-in-one" aquarium with similar dimensions were available, I would have grabbed one in a heartbeat! An AIO aquarium can have surface skimming, "filtration", and a place to hide the heater all in one convenient, aesthetically clean design. 

IMHO, the lack of AIO's with more interesting dimensions and sizes is one of the great missed opportunities in the aquarium industry. I think they'd be "smash-hit" sellers...Someone needs to take the chance and step up! Better yet- some manufacturer needs to consult with me on this....😆

Oh, but this piece isn't about my rantings against the aquarium industry, so let's get back to the topic.

So, managing this aquarium really couldn't be easier. My maintenance procedure includes exchanging 1 gallon/4L of water a week, cleaning the surface skimmer, and wiping away any algae I might encounter on the front glass (since the tank gets partial sun at certain times of the day, once little section of the glass occasionally gets. little algae film).

And that's it. Easy. Literally, this tank is on cruise control. Oh , I do add .50ml of Seachem Flourish Excel three times a week. I have yet to need to "top off" the leaves in the tank, as oak is pretty durable and tends to hang around a very long time before completely breaking down. 


One of the cool things about a botanical method aquarium like this one is that you can observe the fungal bloom and gradual decline among the leaves, and upon the oak branches. Initially, there was significant fungal growth among the leaf litter, in particular. 


However, as always occurs in botanical method aquariums, the initial significant bloom of fungal growth always subsides to a vary manageable, more "aesthetically pleasing" level, and remains that way for the duration of the aquariums existence. 

It's yet another one of those "mental shifts" we ask you to make as a botanical method aquarium keeper. Being patient with your aquarium as it evolves. And the beautiful thing is that, when you do this, the aquarium often becomes something better than you initially envisioned. 

The beauty of an aquarium like this one is that you can make a few "tweaks" to the theme along the way without issues, as we've discussed many times. This type of "baseline" "leaf-litter-centric" tank gives you a track to run on, and then you can make subtle changes without impacting the "operating system" of the aquarium.

In the end, living with your botanical method aquarium isn't just about a new aesthetic approach. It's about understanding and processing what's happening in the little aquatic ecosystem you've created. It's about asking questions, modifying technique, and playing hunches- all skills that we as hobbyists have practiced for generations. 

When you distill it all- we're still just "keeping an aquarium"...but one that I feel embraces a far more natural, dynamic, and potentially game-changing methodology for the hobby. 

Stay creative. Stay flexible. Stay excited. Stay bold. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

February 03, 2022


The process: The "How and Why?" of Botanical Preparation...

Some 7 years into the adventure that is Tannin Aquatics, and the world of botanical method aquariums seems to be exploding! There are more hobbyists creating these types of aquariums than ever before, more vendors offering botanical materials, and more information!

And of course, there is lingering confusion and even mis-information. The kind of stuff that can confuse any newcomer to our little sector, and actually prevent many people from succeeding with these types of aquariums. There is a surprisingly large amount of bad information out there on some of the most basic processes we employ.

To this end, I think it's time for me to do a periodic review of some of the fundamentals of our practice and processes. Let's start with one of the most basic- the art and science of botanical preparation.

"Preparation required..."

Words you've heard us utter again and again; precautions you've seen us advise you to take. You see it on our packaging, hear it discussed on "The Tint" podcast, and read about it in articles we publish here and elsewhere. Yet, there appears to be some confusion about what exactly we mean by "preparation."

Yeah, it's not a secret that, before you throw those seed pods and leaves into your aquarium, you need to do some preparation.


And why are we talking about this again?

Well, seriously, I still receive about 3-4 emails every single week from customers of ours (and from others, apparently!) asking what to do with botanicals after  they receive them...So, it's obvious to me that some people just aren't seeing this stuff, hearing it, reading our instructional cards, social media posts, etc., or not getting advice from the people they purchased their leaves, or whatever from. (Isn't EBay great! What a resource for serious hobbyists!)




I know, it's starting to sound a bit repetitive...

However, with the world botanical-style aquariums growing at an exponential rate, and more and more hobbyists entering into the fray- many of whom are enamored by the beautiful aesthetics of these tanks, it's important-well, actually essential- to revisit this stuff again and again.

And really, because most of the new vendors into our market space simply appropriate much of the information we put out to help the community, and use it to push their products, let's at least give those lazy-ass motherfuckers something useful to share (and since they're not bothering to provide this information, themselves...)!

Okay, mini-hate-rant over. For now.

"So, you're really into boiling and steeping botanical, huh?

Yes. I am. That's my thing.

"Why do you do that?"

Consider that boiling water is used as a method of making water potable by killing microbes that may be present. Most nasty microbes essentially "check out" at temperatures greater than 60 °C (140 °F). For a high percentage of microbes, if water is maintained at 70 °C (158 °F) for ten minutes, many organisms are killed, but some are more resistant to heat and require one minute at the boiling point of water. (FYI the boiling point of water is 100 °C, or 212 °F)...But for the most part, most of the nasty bacteria that we don't want in either our tanks or our stomachs are eliminated by this simple process.

So, wouldn't it make sense to boil, or at least steep, our botanicals before we dump them into our aquariums?

Yeah, it would.

Ten minutes of boiling is "golden" to assure a "good kill", IMHO. Of course, we boil for other reasons, too-as we'll touch on in a bit.

The most important reason that we boil botanicals is to kill any possible microorganisms which might be present on them. Leaves, seed pods, etc. have been exposed to rain and dust and all sorts of things in the natural environment which, in the confines of an aquarium, could  introduce unwanted organisms and contribute to the degradation of the water quality.

And, the surfaces and textures of many botanical items, such as leaves and seed pods lend themselves to retaining dirt, soot, dust, and other atmospheric pollutants that, although quite likely harmless in the grand scheme of things, are not stuff you want to start our with in your tank!

So, we give all of our botanicals a good rinse with fresh water.

Then we boil them.

Boiling also serves to soften botanicals. This is important to do for a number of reasons...

Well, the most obvious to us is thats it helps saturate the tissues of the botanicals and make them sink. I mean, who wants a bunch of floating seed pods and leaves in their aquairum? Wait, don't tempt me here...

If you remember your high school Botany (I actually do!), leaves, for example, are surprisingly complex structures, with multiple layers designed to reject pollutants, facilitate gas exchange, drive photosynthesis, and store sugars for the benefit of the plant on which they're found. As such, it's important to get them to release some of the materials which might be bund up in the epidermis (outer layers) of the leaf.  As we get deeper into the structure of a leaf, we find the mesophyll, a layer of tissue in which much of photosynthesis takes place.



We use only dried leaves in our botanical style aquariums, because these leaves from deciduous trees, which naturally fall off the trees in seasons of inclement weather, have lost most of their chlorophyll and sugars contained within the leaf structures. This is important, because having these compounds present, as in living leaves, contributes excessively to the bioload of the aquarium when submerged...

Personally, I feel that we have enough bioload going into our tanks, so why add to it by using freshly-fallen leaves with their sugars and such still largely present, right? I mean, it's definitely something worth experimenting with in controlled circumstances, but for most of us botanical method aquarium geeks, naturally fallen, dried leaves are the way to go.

The analogs to processes which occur in wild aquatic habitats are incredible, and part of the reason why, if left to "do their thing", that botanical method aquariums run in such a stable manner. 

When leaves are placed into the water, they release some of the remaining "solutes" (substances which dissolve in liquids- in this instance, sugars, carbohydrates, tannins, etc.) in the leaf tissues rather quickly. Interestingly, this "leaching" is known by science to be more of an artifact of lab work (or, in our case, aquarium work!) which utilizes dried leaves, as opposed to fresh ones.

The most important part of the process of utilizing botanicals in leaves in aquariums is analogous to the natural process of decomposition, which ecologists call the "conditioning phase", during which microbial colonization on the leaf takes place. Bacteria begin to consume some of the tissues of the leaf- at least, softening it up a bit and making it more palatable to fungi.

This is, IMHO, the most important part of the process. It's the "main event"- the part which we as hobbyists embrace, because it leads to the development of a large population of organisms which, in addition to processing and exporting nutrients, also serve as supplemental food for our fishes!

The botanical material is broken down into various products utilized by a variety of other life forms. The particles are then distributed throughout the aquairum by the currents and are available for consumption by a variety of organisms which comprise aquatic food webs.

Six primary breakdown products are considered in the decomposition process: bacterial, fungal and shredder biomass; dissolved organic matter; fine-particulate organic matter; and inorganic mineralization products such as CO2, NH4+ and PO43-

This is exactly what happens in Nature. And that's why we prepare our botanicals- because "prepared" botanical materials literally "kick start" the ecology of the aquarium! 

An interesting fact: In tropical streams, a high decomposition rate has been related to high fungal activity...these organisms accomplish a LOT!

So, yeah, that's perhaps the biggest reason why we prepare leaves for aquarium use!

Are there variations on this prep theme?

Well, sure. Of course! 

Many hobbyists rinse, then steep their leaves in boiling water, rather than a prolonged boil, for the simple fact that exposure to the newly-boiled water will accomplish the potential "kill" of unwanted organisms, which at the same time softening the leaves by permeating the outer tissues. This way, not only will the "softened" leaves "go to work" right away, releasing the beneficial tannins and humic substances bound up in their tissues, they will sink, too! 

And of course, I know many who simply "rinse and drop", and that works for them, too! And, I have even played with "microwave boiling" some stuff (an idea forwarded on to me a few years back by aquascaper Cory Hopkins). It does work, and it makes your house smell pretty nice, too!

It's not a perfect science- this leaf preparation "thing."

And I admit, I've changed some of my approaches over the years...I'd be foolish not to. 

Of course, the fundamental idea behind preparation of botanicals hasn't really changed too much. And the underlying rationale hasn't changed, either. 

Leaf preparation has evolved quite a bit, actually! Many aquarists have developed simple approaches to leaf prep that work with a high degree of reliability. Now, there are some leaves, such as Magnolia, which take a longer time to saturate and sink because of their thick, waxy cuticle layer. And there are others, like Loquat, which can be undeniably "crispy", yet when steeped begin to soften and work just fine.

There is no 100% guaranteed way to perfectly prep every botanical or leaf the same way every single time.

You have to be flexible and adaptable.

So why do we soak after boiling?

Well, it's really a personal preference thing.I suppose one could say that I'm excessively conservative, really.  Do you HAVE to?

No. However....

I feel that it releases any remaining pollutants and undesirable organics that might have been bound up in the leaf tissues and released by boiling, which is certainly arguable, but is also, IMHO, a valid point. And since we're a company dedicated to giving our customers the best possible outcomes- we recommend being conservative and employing the post-boil soak.

The soak could be for a half an hour, an hour or two, or even overnight...no real "science" to it. Some aquarists would argue that you're wasting all of those valuable tannins and humic substances when you soak the leaves overnight after boiling. I call total bullshit on that. My response has always been that you might lose some, but since the leaves have a "lifespan" of weeks, even months, and since you'll see tangible results from them (i.e.; tinting of the water) for much of this "operational lifespan", an overnight soak is no big deal in the grand scheme of things.

So don't stress over that, okay?

Do what's most comfortable for you- and okay for your fishes.

When it comes to to other botanicals, such as seed pods, the preparation is very similar. Again, most seed pods have tougher exterior features, and require prolonged boiling and soaking periods to release any surface dirt and contaminants, and to saturate their tissues to get them to sink when submerged! 


And quite simply, each botanical item "behaves" just a bit differently, and many will require slight variations on the theme of "boil and soak", some testing your patience as they may require multiple "boils" or prolonged soaking in order to get them to saturate and sink.

Yeah, some of those damn things can be a pain! 

However, I think the effort is worthwhile.

Now, sure, I hear tons of arguments which essentially state that "...these are natural materials, and that in Nature, stuff doesn't get boiled and soaked before it falls into a stream or river."

Well, damn, how can I argue with that?

The only counterargument I have is that these are open systems, with far more water volume and throughput than our tanks, right? Nature might have more efficient, evolved systems to handle some forms of nutrient excesses and even pollution. It's a delicate balance, of course.

I believe that some steps to prepare botanicals before adding them to our aquariums is not only beneficial because it helps to cleanse them of some of the aforementioned pollutants- the practice itself creates "ritual" in our speciality, which in turn, helps to create "best practices" which can benefit all who play with these types of aquariums.


In the end, preparation techniques for botanical materials are as much about prevention as they are about "preparation."

To summarize- by taking the time to properly prepare your botanical additions for use in the aquarium, you're doing all that you can to exclude unwanted bacteria and microorganisms, surface pollutants, excess of sugars and other unwelcome compounds, etc. from entering into your aquarium. 

And, most important, you're readying your botanical materials to support the ecology of the aquarium.

Like so many things in our evolving "practice" of perfecting the blackwater, botanical-method aquarium, developing, testing, and following some basic "protocols" is never a bad thing. And understanding some of the "hows and whys" of the process- and the reasons for embracing it-will hopefully instill into our community the necessity- and pleasures- of going slowly, taking the time, observing, tweaking, and evolving our "craft"- for the benefit of the entire aquarium community.

The practice of botanical-method aquariums is still very much "open source"- we're all still writing the "best practices"- and everyone is invited to contribute! 

That's part of the fun, isn't it?

It is.

Stay engaged. Stay fascinated. Stay observant. Stay excited. Stay involved...

And Stay Wet.


Scott Fellman

Tannin Aquatics


February 01, 2022


A beautiful Mess: Detritus and its role in our aquariums...AGAIN!

I don't usually make claims, but I will bet that I probably talk more about detritus than anyone else in the aquarium hobby...And I'll go out farther on a limb and claim that I probably have more good stuff to say about detritus in the context of our tanks than just about anyone in the aquarium hobby!  

I've covered the topic more times than I care to repeat, but, let's face it- detritus is an essential and important component of the botanical method aquarium, and it's been maligned and misunderstood over the years.

Ecologists define detritus as,   "... partially decomposed organic matter from plant and animal tissues, in addition to microorganisms and minerals."

The Aquarium Wiki (a nice source for the hobby) has a less nuanced definition: 

"...dead particulate organic matter. It typically includes the bodies or fragments of dead organisms, as well as fecal material. Detritus is typically colonized by communities of microorganisms which act to decompose or remineralize the material."

That's a pretty thorough definition, isn't it?

Note that nowhere in either definition do you see references to the stuff being "dangerous" or "detrimental" to fishes or aquariums. Now, look, having an excess of just about anything accumulating somewhere in the closed environment of an aquarium has an impact that you'll have to deal with somehow, or at the very least, have an understanding of.

I know that uneaten food and fish poop, accumulating in a closed system can be problematic if overall husbandry issues are not attended to. I know that it can decompose, overwhelm the biological filtration capacity of the tank if left unchecked. And that can lead to a smelly, dirty-looking system with diminished water quality. I know that. You know that. In fact, pretty much everyone in the hobby knows that.

Yet, as a hobby, we've really sort of heaped detritus into this "catch-all" descriptor which has an overall "bad" connotation to it. Like, anything which is allowed to break down in the tank and accumulate is bad. Anything that looks like "dirt" is...well, "dirty", dangerous, and should be treated accordingly.

Now, "dirty-looking" and "dangerous" are two very different things, right? Do natural habitats look "dangerous" to the life forms which reside in them?

In botanical-method aquariums, if most of what is accumulating in your mechanical filter media and on the substrate, etc. is just broken-up, decomposing bits of botanicals, I'd have little concern. That's what happens to terrestrial materials in an aquatic environment. It's normal for these types of aquariums. As we've discussed ad infinitum here, various organisms, like fungi, etc., work to break down these materials and begin the decomposition process.

Now, if it's uneaten food that you're seeing accumulate in excess, then you need to figure out a more accurate feeding approach. Same with fish waste. At the very least, you likely need better circulation and mechanical filtration within your system. And of course, you need to address why it is you have so much uneaten food accumulating in your system!

Left unchecked, accumulations of uneaten food and fish waste can tax the biological filtration capacity of your aquairum .

"Detritus" in general, in my opinion, gets a kind of a bad rap, as the bulk of it is really broken down already by the time it accumulates in the aquarium. And there is a valid argument that this material, if allowed to settle in the aquarium, becomes a basis for biofilms/fungal growth- part of the "food web" in our tanks. Think about this:  Organisms which function as "decomposers" take up substances such as nitrate and phosphate from the surrounding waters while utilizing detrital material to build new biomass! It's important for them...and for the ecology of your aquairum.

The biomass in detritus can oxidize dissolved organic compounds and ammonia and convert them into relatively harmless gases and nitrate.

And, when we value and accommodate beneficial microorganisms, we help them make detritus more palatable to detritivores! So, in an aquarium which encourages the growth of bacteria, fungi, copepods, etc., the organic material contained in detritus becomes part of the food web. Everybody up the food chain can benefit from the stuff.

By going "full ham" and siphoning every last speck of detritus in our tanks, your essentially breaking this chain, and denying organisms at multiple levels the chance to benefit from it! And, you're effectively destroying an established community of microorganisms which serve to maintain high water quality in the closed environment of an aquarium!

"Anomalous" ammonia spikes and such often have their origin in over-zealous cleaning of aquariums and filter media. Taking out all of the "fish shit" is actually removing a complex microbiome that's keeping your tank healthy!

I've seen numerous articles over the years denouncing detritus as a "nuisance", and then in the same article, acknowledging that it can be "useful" if you keep plants, or are raising fry, or keeping fishes which graze on the stuff...

The "bad" narrative seems to win out, though.

Ask yourself this: If detritus is sooo bad for fishes, how come the standard "beginner's advice" for years has been to "inoculate" your new aquarium with filter media or substrate, detritus and all, from an established, healthy aquarium? I mean, c'mon! 

The indictment in most of the articles that I read on the topic is that it's "bad" for indeterminate reasons, and that you should remove it from your tank because it "looks bad."

That's not exactly a scientifically compelling reason to eliminate detritus from your tank, is it?

About the best case I've seen to not have excesses of detritus accumulate in a typical aquarium is that they do contain bacteria. And, for some fishes which continuously come in contact with it, like bottom-dwelling catfishes, it requires them to mount a bit of an immune response to the bacteria (harmless or not) contained in the detritus, leaving their immune systems taxed and slightly less "available" to resist legitimate illnesses. Perhaps a bit of a "stretch", but it seems to make some sense to me.

That being said, I wonder how much of this stuff is really accumulating in a well-managed, under-populated, and carefully-maintained aquarium? Sure, in systems with large, predatory cichlids and messy eaters, you're likely to see a lot more than you would in a lightly-stocked tank with say, Endler's Livebearers or Gouramis, but still...do most of us really overfeed THAT much?

I don't think so. I mean, I hope not.

Of course, if you see uneaten food and such accumulating in your tank, it looks crappy. It's a sign of poor husbandry. With this undefined "detritus" that you may see, however, do you have phosphate or nitrate issues as a result of accumulating organics from this stuff, or is some of it- enough of it- being utilized by bacteria and other "unseen residents" of your tank that it's not really a "problem" from an environmental standpoint?  What does the test kit say?  Do you have massive excess algal growths? A depressed oxygen level in the tank? 

Or does it just look sloppy?

Is this another case of us in the aquarium hobby making a grand pronouncement like, "It looks shitty, so it's always bad!" yet again?

I think so.

Ahh, "detritus"- menace or benefit? Or perhaps, something in between? Like biofilms, fungal growth, aufwuchs,and decomposition- is it something that is inevitable, natural- perhaps even beneficial in our aquariums? Or, is it something that we should learn to embrace and appreciate? All part of a natural process and yes- aesthetic- that we have to understand to appreciate?

The natural habitats seem to have plenty of it.

Fellow hobbyists keep asking me my thoughts about detritus, and I admit, they have evolved over the years. I think so many things in moderation are pretty good- even things that we have historically "freaked out" about. Yes, hardly a scientific conclusion, but I think valuable from an aquarium management perspective.

It's about moderation. It's about going beyond the superficial.

Part of it is a "mental shift" that we have to make. Again. Understanding that, in Nature, detritus is abundant, common, and vital to the health of aquatic ecosystems.

Let's shift our focus just bit to one of the more "practical applications" for detritus- as a food source for fishes.

To a certain extent, detritus is a part of the diet of almost every fish. If you're into reading and studying gut content analysis of fishes like I am, you'll see "detritus" mentioned in virtually every single one. The percentage of the diet that detritus comprises varies from species to species, but it's ubiquitous.

And of course, if you observe the behavior of many of your fishes in the aquarium, such as characins, cyprinids, Loricarids, and others, you'll see that in between feedings, they'll spend an awful lot of time picking at "stuff" on the bottom of the tank. In a botanical method aquarium, this is a pretty common occurrence, and I believe an important benefit of this type of system. 

I am of the opinion that a botanical-method aquarium, complete with its decomposing leaves and seed pods, can serve as a sort of "buffet" for many fishes- even those who's primary food sources are known to be things like insects and worms and such.

Well, I may favor little fishes like characins and Rasbora in my tanks, but I do have a healthy respect-and admiration for some of the more- shall we say- "hardcore" fishes...like the so-called "Eartheaters" (families Acarichthys, Biotodoma, GeophagusGuianacaraGymnogeophagus, and Satanoperca).

I'm asked a lot ab out keeping these fishes in botanical-method aquairums. It seems to me they'd be pretty good inhabitants, actually! And no discussion on detritus would be truly complete without talking a little about these fishes.

This lively and diverse group contains some of the most endearing and interesting cichlids around. With a surprising number of our customers wanting to incorporate botanicals in setups with these fishes, I had to chime in here in "The Tint", right?  And since they tend to be associated with detritus....yeah.


(Gymnogeophagus balzanii. Photo by CHUCAO, under CC BY-SA 3.0)

And of course, the name of the genus Geophagus contains the Greek root words for "earth" and "eat", as if to reinforce the popular collective name. So, in case you haven't figured it out by now...they dig in the sand to get food...oh, and they shit....

A lot.

But you probably already knew that, and, not exactly known for my love and devotion to cichlids,  I'm like the last guy you really want to write one of those "Review of the Eartheaters"-type articles, so we're going to focus more on the interesting dietary preferences of these fishes, and the kind of environment you'd want to create in your aquairum for these bad-asses, from a botanical perspective, of course.

First off, let's talk about their diet.

These fish ingest  just about any decomposing material...leaf litter, botanicals, etc... that they can. They sift through it and other materials in the substrate to derive their nutrition. And, if you go just a bit deeper than you see on the typical hobby website information... 

What do they actually eat in the wild? Well, here is another one of those trusty gut content analysis which I found in a research paper on a few species of Geos:

Insects (terrestrial). 6.5%

Trichoptera larva 6.5%

Chironomidae larva 2.33%

Coleoptera larva. 3.83%

Coleoptera adult 3.83%

Ostracods 1.3%

Vegetation/detritus 77%

That's a LOT of detritus!

Detritus is an extremely "available" food resource, not subject to seasonal and regional shortages and other factors. It's everywhere, pretty much all the time. Because of its composition, detritus is something that has been available as a food resource for fishes for untold millennia. Water chemistry and seasonal availability WILL at least impact the composition of the detritus at any given time, but that's about it. Detritus is a really good food source! 

Detritivores, in general, are responsible for the fragmentation of plant and animal debris and conduct what ecologists call "inoculation" of the rejected material with microorganisms that complete the decomposition process. And of course, that  makes nutrients from detritus available for plant uptake within the ecosystem.

Detritivorous fish have physiological adaptations in the digestive process to extract large amounts of nutrients from detritus, since it provides less energy and protein than other types of food.  The digestive tract of detritivorous fishes is characterized by a small, muscular stomach, and an extremely long intestine, to facilitate a high rate of absorption and assimilation of nutrients by the fish. According to ichtyologists, this characteristic long intestine can vary from 3 to 10 times the body size among detritivorous species.

The elongated intestine is curled and folded extensively to fit inside the body cavity, which results in a long intestinal contact and passage time. This effectively keeps the ingested detritus in contact with digestive enzymes for an extended period of time, ensuring the maximum possible extraction of nutrients by the fish.

In wild aquatic habitats, detritus is comprised of many things; however, in places like the Amazon basin, it's been determined through gut-content analysis that a high percentage of the detritus consumed by fishes is composed of plant materials- leaves, seed, and wood, as well as components of terrestrial grasses, like Paspalum, which is abundant in this region.

Geophagus are what are known to scientists as "benthopagous" - meaning that they derive most of their nutrition by ingesting large amounts of substrate and sediment, and sift for food organisms and detritus, expelling the undigestible material through their mouth and gills.

Hence, the origin of the popular name,  "Eartheaters!"

While these fishes do ingest detrital material (which isn’t particularly nutritious), they do so mainly to consume and assimilate the associated microbial growth in the detritus.

Now, let's be perfectly up front: These are larger, messy fishes. If you're thinking that you can create a beautiful, elaborate aquascape for them, and that they would leave it nicely intact, you're in the realm of fantasy. They will spend large parts of their day digging and sifting and upending whatever is in their way.

You need to accept a different sort of aesthetic: The one that the fishes will create, wether you like it or not! One that will have substrate continuously moved about, and whatever material is contained within the substrate either put into suspension within the water column, or collecting on the surface of the substrate. Good circulation and filtration are essential.

(Gymnogeophagus balzanii. Photo by CHUCAO, under CC BY-SA 3.0)

It means oversized filtration- likely canisters, or even the newer automatic filter roll systems in a sump (this would be the best way to filter a system containing a population of these fishes, IMHO.)

I wouldn't even attempt to keep these fishes without radically "over-filtering" their aquarium. It will just keep you from going crazy.

Now, that being said, if properly filtered, you could - and should- include botanical materials and leaf litter in their aquairums.  What? All of the "experts" say no way? Okay, have the experts actually kept their tanks with these fish with an automatic filter roll and leaf litter and botanicals? 

Yeah, I didn't think so. 

Besides, these fishes will absolutely ingest large amounts of leaf litter and other botanical materials to derive some of their nutrition, as we discussed above. This is what they do in the wild. It's what they're evolved to do. We just need to manage our expectations and consider how an aquarium designed to accommodate voracious detritivores looks and should be run for long term success.

(Satanoperca leucosticta- image by Dr. David Midgely, used under CC BY-SA 2.5)

As you know by now, many botanical materials have significant amounts of lignin and cellulose, which are thought to be necessary for the health of these fishes.

So, yeah, why NOT try to keep Geos in a botanical-method aquarium?  Damn, I can't believe that I just devoted a fairly respectable amount of time to discussing Geos in "The Tint!" 

However, it was in relationship to my main argument about the usefulness of "detritus" in our aquariums. The bottom line (pun intended) is that I don't see detritus as a "nutrient trap" in the aquarium. 

Rather, it's it a place for fishes to forage in and among. 

A place for larval fishes to seek refuge and sustenance in. Kind of like they do in Nature, and have done so for eons. Yes, we're talking about a closed ecosystem here, which doesn't have all of the millions of minute inputs and exports and nuances that Nature does, but structurally and functionally, we have some of them at the highest levels (ie; water going in and coming out, food sources being added, stuff being exported, etc.).

I think we really need to think about our systems- particularly in the botanical-method aquarium world- as little microcosms, which replicate- at least on some level, some of the process which occur in Nature to create a specialized but highly productive and successful- not to mention, dynamic- ecology. 

There is so much more to this stuff than buying in unflinchingly to generalized statements like "detritus is bad."

It's a mental shift.

One which we should all consider making.

Stay thoughtful. Stay curious. Stay open-minded. Stay adventurous...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



January 29, 2022


The common thread of my fishy obsessions...

It's not very often that I become obsessed with a fish.

Oh, sure, it's happened quite a few times over the years, but when you "amortize" it out over a lifetime in the hobby, it's a shockingly infrequent occurrence for me! The fishes which have reached "obsession" level with me are varied, and the list includes some choices which, for whatever reason, simply grab me on some particular level. And when I sort of analyzed my favorites, some interesting "commonalities" became evident.

Each one was very well suited for the botanical-method aquariums that I play with, and look and behave amazingly in these systems.

The Sailfin Characin, Crenuchus spilurus, was likely the first fish which really grabbed me. It wasn't just the fish; it was the "whole package"- the meaning of the Latin genus name, ("guardian of The Spring" )the habitats it comes from, it's unusual, almost "cichlid-like" behavior, and the fact that it caught my eyes when I was like 8 years old, scrutinizing my dad's well-worn copy of the classic William T. Innes book, "Exotic Aquarium Fishes."

When I finally found these fishes, after literally three decades, I pounced and purchased a group. They did not disappoint! They are fascinating fish, with an almost creepy, mysterious presence about them. As anyone who's kept them can attest, they sort of "appear" out of nowhere in your tank, and disappear just as mysteriously, fading back into the shadows. Wow!

There pretty cool!


Honestly, if a fish could earn the moniker "cool", the Diptail Pencilfish, Nanostomus eques, would be it. It's absolutely not an overstatement to declare that these Pencilfishes have distinct personalities! They're not "mindless-drone, stupid schooling fishes", like some of the Tetras. (Sorry, my homies...Love ya' lots, but alas- you have no individual personalities...😂)

There's a bunch of unique aspects to this fish's behavior which I find enormously compelling. The Latin name of the species, eques, means "knight", "horseman", or "rider", in reference to this species’ unique oblique swimming angle. 

Ah, that "oblique swimming angle" thing. Yeah, they swim at an angle of about 45 degrees facing upwards. This angle is thought to give them an advantage in feeding. They see insects and such that fall from overhanging vegetation better than their horizontally-oriented buddies do. They get more food that way. Simple.

What I really love about these fish is that they are incredibly curious and obviously intelligent, checking out just about anything which goes on in their aquarium. You get the feeling when observing them that they are acutely aware of their surroundings, and once acclimated, are cautious, but pretty much fearless. A fellow hobbyist once told me she thinks they're the freshwater equivalent of Pipefish...and that sounds about right..I agree with that 100%!

Perhaps "Diptails" are my fave fish of all? 

And then came the "Black Ghost Knife Fish", Apteronotus albifrons. Again, it goes back to my childhood. Reading one of Herbert Alexrod's books, "Exotic Tropical Fishes", and the fantastic story about the legends behind the fish, and how it was revered by the South American tribes as a repository for the souls of their departed ancestors...

An intriguing and alluring tale for a young kid, for sure! They weren't farm raised like they are now. They were all wild-caught, which made them even more intriguing to me! And when I would actually see them in the LFS, they were (at the time) mind-bogglingly expensive, at like $25.00! (Hey, I was like 11 yrs old). Add to the fact that the fish was super-intelligent, nocturnal, and just plain weird looking, and it was destined to be a lifetime fave of mine. 


Killifish always held an almost irresistible appeal to me. I guess it was the habitats which they came from, their method of reproduction and egg incubation, and the fact that I rarely, if ever, encountered them in the fish stores. It was only after I joined the American Killifish Association at age 15 that I was really able to indulge myself. I tried and loved many different species, however, my all-time favorite was, and still is, Epiplatys dageti "Monroviae", a top-spawning fish.

It's regarded as a "beginner's killie" because it's easy to keep and spawn. It was the first killie I ever kept and bred, and almost everything about the fish appealed to me the minute I encountered it! In fact, almost any species in the rather subtly-colored genus Epiplatys captivates me, but this one remains my most loved killie!

I was never a big catfish person. I never really became obsessed with them the way some hobbyists do. Regardless, there was one species which grabbed my attention" Pecklotia compta, the so-called "L134 Leopard Frog" Pleco. I think it was the color pattern that grabbed me first. And then, upon learning more about them,  it was the smaller size, it's social habitats, its xylphagic dietary preferences, and its endearing behavior which lured me in.

I was first able to obtain a captive-bred specimen in 2016, and since them, I]ve never been without one. I currently have three of them, most recently acquired from my friend (and guest on "The Tint" podcast), master breeder Sumer Tiwari, and they have genuine "personality" and are absolutely some of the most entertaining fish I've ever kept- even though they seem to sleep most of the day!

You've gotta respect THAT!

More recently, it was the little Tucano Tetra, Tucanoichthys tucano, whcih grabbed me. A tiny, incredibly attractive little characin, hailing from a very specific habitat, replete with roots and leaves. There was virtually no way I could resist this fish, and creating a dedicated biotope-inspired aquarium for it was literally my destiny! When I did a little googling and found the type paper by Gery, et al,  with the original description of the fish, I knew that this one which I had to keep.

The paper included a few tantalizing tidbits about the locality where the fish was collected, and gave me a lot of good data that would help me re-create the function aspects of its habitat. And it required a commitment. These little tetras cost around $12 USD each- for a tiny fish, that's a LOT of money! And again, worth it in every respect. It was- and is-very easy to fall for this fish!

I have to admit one heretical thing: I am not a huge fan of cichlids. I know, that's like crazy to hear in this hobby, but it's true. Most of them simply do nothing for me. I see most as big, messy, mean, destructive fish. Oh, sure, I love Angels and Discus, but I have no desire to dedicate a large aquairum to them and their fussy habits (Shit, I'll take a stony coral tank any day over a bunch of prima donna Discus!). I've kept some Apistos- and they are cool, but they never really "grabbed" me.

However, the one that did, is the diminutive and interesting Dicrossus filamentosus, the "Checkerboard Cichlid". I think the reason why is the fact that this fish is peaceful, small, won't spawn every week, saddling you with 500 fry that you don't want, and the fact that it's from blackwater habitats, filled with leaf litter and tangled roots.  I have kept groups of these in botanical-method aquariums on multiple occasions, and they have always proven to be terrific additions to a peaceful community.

Perhaps the most recent addition to my "Obsession List" is "Valiant's Chocolate Gouarami", Sphaerichthys vaillanti. This fish came to my attention years ago, when studying the unique peat swaps and blackwater streams of Borneo. If ever there were a fish that was perfect for its habitat, this could be it! It was one of those fishes that, once I started keeping, I had to wonder why I had never kept it before!

Looking for all the world like a leaf at times, this small, peaceful, and altogether endearing fish captured my attention early on. When I decided to set up an aquarium modeled on these cool habitats, I emphasized leaf litter and branches, adding in the (for me) unusual choice of live aquatic plants (Mircorsorum sp., "Java Fern") to further keep their environment shaded, providing comfort for the fish and bringing out their natural colors and behaviors. 

It's a fish that might have changed my perception of Gouramis (which I always liked, anyways) from being "nice but not essential" fishes for my collection to "ones to obsess over!"



It becomes obvious to me, when I really start looking at things analytically, that my favorite fish choices seem to reflect a preference for specific habitats or ecological niches. Almost all of my faves tend to come from smaller tributaries and streams, with moderate to minimal current or water movement. These habitats are typically filled with leaf litter, branches, and submerged root systems. 

Many of my favorite fishes come from flooded forests (no surprise there..), or other seasonally-inundated habitats, and have specialized feeding, spawning, and foraging habits as an adaptation to these environments. Most are dimly lit, devoid of aquatic plants, with deeply-tinted water and lots of overhanging terrestrial vegetation. 

Most of them feed on allochthonous inputs (stuff that comes from outside the aquatic environment) like insects, small fruits, and flowers. Some display unusual dietary preferences, such as eating detritus, fungal growths, or lignin from submerged wood and roots. Pretty much all of them spend large amounts of time foraging.

Another common denominator of these fave fishes is that they are intimately tied to their environments. They move within, or migrate among similar habitats throughout most of their lives. As aquarium fishes, they categorically seem to do better long term when kept in tanks which replicate, to some degree, the function and form of their natural habitats. These aquatic habitats are profoundly influenced by the terrestrial habitats which surround them.


I think that this love for the fishes and the allure of their natural habitats is what drew me to the whole idea of botanical method aquariums. I believe that the environments themselves are as interesting and compelling as the fishes which inhabit them. I've dedicated a substantial portion of my life as a hobbyist to studying, understanding, and attempting to replicate the function aspects of them in my aquariums.


 My love for these fishes and their habitats is very much evident in the "DNA" of Tannin Aquatics, too.

It's what this whole thing is all about.


The other common denominator among my fish choices is that most of them are not exactly what most people would call "colorful." In fact, the bulk of them tend to be brown, black, or grey, or some combination of the three! Rather, they are "earthy" looking fishes, perfectly "designed" to compliment the environments from which they come. 


I think- actually, I'm certain- that this coloration thing is one of the other things which attracts me to many of them. This subtle, interesting, and remarkably complex coloration is something which I find compelling. From a purely aesthetic standpoint, the fishes compliment their surroundings, and become a part of it, rather than standing out and placing the habitat in the background. 

In the botanical method aquarium, it's great to have a little pop of color against the deep, rich colors of leaves, seed pods, and wood, and the tinted water. However, one of the surprising things I discovered years ago is that the more subtle fishes tend to "pop" more in blackwater tanks. Now, "surprising" not in that they display better colors- the environmental conditions we create obviously assist in that- but "surprising" in that they tend to catch your eyes more than you might expect.

Even the more cryptically-colored-and shaped fishes do this. In fact, they are somewhat more engaging in this setting than the more obvious, brightly colored fishes, IMHO.

(Farlowella vittata- another fave of mine...)

Now, some of these fishes do have flashier colors at times, which make them a bit more exciting to some people, I suppose. In the case of Crenuchus spilurus, the males have an extended dorsal and anal fin, and are larger and more colorful than females. Yes, "colorful" is relative here, but when you see a group- you'll notice the sexual dimorphism right away, even among juveniles.

What really gets me going with my fave fishes, though, is their behaviors- or how they interact with their environment. For example, the Sailfin Characin...

Individuals of this species spend a lot of their time sheltered under dead leaves, branches, roots, and aquatic plants. They tend to "hover", and don't dart about like your typical Tetra would. In fact, their behavior reminds me of the Dartfishes of the marine aquarium world...They sort of sit and flick their fins, often moving in slow, deliberate motions. Communication? Perhaps.

The Sailfin feeds during the daylight hours, and spends much of its day sheltering under branches, leaves, and root tangles, and is a mid-water feeder, consuming particulate organic matter, such as aquatic invertebrates, insects, bits of flowers, and fruits...Even the dietary preferences of this fish give you some idea of the habitat from which it comes, and gives you some inspiration to replicate aspects of it within the aquarium. 

Let's talk a bit more about how the environments in which fishes are found can affect their behavior, or how they interact with the aquarium that you create? 

My overarching suggestion?

Create the aquarium environment around the specific fish you want to keep.

Really.  I know, that is hardly ground-breaking. However, I think that lately, more tanks are designed around...the "aquascape" and the fishes are sort of "force fit" into them. I mean, "arches and tunnels" might be neat to look at, and fishes will swim through them...But what about modeling structures found in the habitats they come from? How many brightly-illuminated tanks with Green Neon Tetras or Kubotai Rasbora seem to overlook the fact that these fishes often come from tangled, turbid, even tinted habitats, with mostly terrestrial influences?

It might be kind of fun-and educational- to study where your fishes are found in the natural streams, lakes, and rivers they come from...and "work backwards." I mean, fisherman have been doing this for eons...why not fish hobbyists?

It makes perfect sense, because, well, we have a pretty fair collective understanding of how fishes interact with their environment, don't we? 

I think so.

Let's briefly discuss some of the more common features in natural bodies of water where fishes are commonly found...this might give you some insight into how to incorporate them into an aquascape. 

I need not discuss flooded forests all that much, because we've pretty much written more on this topic than just about anything over the years...Suffice it to say, my obsession with these unique habitats is well-founded; they are filled with amazing features, ranging from tree trunks to root tangles, to submerged terrestrial plants and leaf litter- all of which we can replicate in the aquarium in dramatic fashion.

And then there are flooded Pantanal meadows- essentially grasslands with low scrub brush and plants, which are flooded seasonally, providing a rich and diverse underwater habitat for a variety of fishes. These habitats, equally as engrossing as the flooded forests, are seldom replicated in the aquarium, for reasons that I cannot quite understand. Perhaps it's the "dirty" aesthetic which has thrown us off? Regardless, the fishes make use of the submerged grasses and vegetation for foraging and spawning among.

And of course, there are many features of streams and rivers that fishes LOVE to congregate in...Think about how you might consciously incorporate some of them into your next aquascape!

First off, a few "sweeping generalities."

Fishes tend to live in areas where the food and protection is, as we've talked about before. Places that provide protection from stronger current, and above-and below-water predators. Places where they can create territories, interact, spawn and defend themselves.

Bends in streams and rivers are particularly interesting places, because the swifter water movement will typically carry food, and the fishes seem to know this. And if theres a tree branch, trunk, or a big rock (or rocks) to break up the flow, there will be a larger congregation of fishes present.

So, the conclusion here is that, at least in theory, if you design your tank to have a higher "open water" flow rate, and include some features like rocks and large branches, you'll likely see the fishes hanging in those areas...

In situations where you're replicating a faster-flowing stream environment, think about creating some little "rock pockets", perhaps on one side of the aquarium, to create areas of calmer water movement. Your fishes will typically orient themselves facing "upstream" to catch any food articles that happen on by.

So, from a design perspective, if you want to create a cool rock feature that your fishes will likely gather in, orienting the flow towards it would be a good way to accomplish this in the aquarium. 

Wow, I can go on and on and talk about my fave fishes and the environments from which they come, but I think you get the picture. I'll be, that if you examine YOUR list of "obsession fishes" closely, you'll find some commonalities, too...I think it's almost inevitable! 

And one of the most exciting things about this hobby is that you can pretty much count on finding some new fish- or fishes- which will catch your fancy. Fishes that you likely haven't even thought about until the moment you stumble on them. Fishes which go from being "Oh, cool fish..." to "OMG, I HAVE to have that one!"

Which species will it be?

It's okay to be obsessed!

Stay excited. Stay curious. Stay engaged. Stay curious. Stay OBSESSED!

And Stay Wet.


Scott Fellman

Tannin Aquatics 



Along the way.

Our approach to aquarium keeping is as much a "mindset" as it is a practice. And, although the practical techniques are relatively easy to grasp and execute, the philosophical components can be confusing and seem a bit contradictory at times.

We preach radical patience, yet completely embrace the idea of dramatically changing things within the greater "mindset."

Huh? Wtf?

Yeah, you should just do what feels right to you.

And sometimes, that means creating an aquarium which doesn't look anything like you'd want it to until long after it's been established. Other times, it means tearing stuff apart immediately and "re-directing" your tank based on a different vision.

Yet, I always urge you to take a slightly longer view of what''s going on in your tank. Not to rush to completely tear your aquarium apart just because it doesn't seem to be getting to where you want it to go right after you set it up.

Stuff takes time.

Looking back on some of my favorite tanks that I've executed in the past few years, it becomes increasingly obvious to me that these systems really didn't completely hit that "look and feel" that I want until long after they'd evolved naturally...however long that took. It seems that , in the botanical-method aquarium, stuff needs to acquire a "patina" of biofilm, a "stain" from the tannins, and decomposition of botanical materials needs to really begin before one of these systems turns "functional" as well.

That's part of why using aesthetics only as an evaluation criteria for a successful botanical-method aquairum falls a bit short, IMHO.

I mean, every new botanical-method tank likely looks cool to a broader swatch of the aquarium world from day one, if you're just using superficial aesthetics as your metric...But the long-established ones stand out for what they really are. After 4-6 months, that's when things get really special. After Nature has done a lot of the real "work" on the tank.

The decomposition of materials in water impacts our aesthetics greatly, as we all know by now. And that is what's so intriguing. The crisp leaves and dry, lifeless twigs that you submerge will evolve into a dynamic, ever-changing microcosm.

Every tank can get there.

Simply by exercisng patience, and letting your aquarium be.

I've long held that perhaps my fave botanical-method aquarium of all was the one I did about 3 years ago..an aquarium utilizing mangrove wood, extensive leaf litter, and catappa bark throughout. This is probably the only tank in recent years that I've truly regretted changing and moving on from! 😂 

I knew what it was I wanted from the tank at the start, but it didn't look like much at first...It would have tested a lot of people's faith if they saw it in it's early stages! 

It literally looked like shit for the first couple of months of it's existence: Slightly tinted water, a contrived-looking "campfire-like" wood stack, bare sand, and mostly intact botanical materials. I had to do a bunch of "iterations" with the hardscape to get it where I wanted it. It looked quite "contrived" at points, but I knew instinctively that if I waited it out, let Nature do Her thing- that the potential was huge in this tank.


Sure enough, a few months in, biofilms started forming. The wood acquired that "patina" we talk about so much. Leaves and botanicals broke down...And the water took on perhaps the most earthy-looking, deeply mysterious color I've seen in a botanical-influenced blackwater aquarium.

By some standards, the water in the tank could be described as almost "turbid"- taking on an appearance as though there were fine materials in the water column. Yet, the tank had a real magical appearance with the lighting; the fishes were as colorful, relaxed and happy as any I've ever seen, and the water parameters were spot-on and consistent for as long as the tank was set up.

The essence of  "wabi-sabi", for sure. Transience, the ephemeral aspects of our botanicals...the wonders of Nature, embraced.

It just took a little time.

I could have "intervened" at a number of junctures- trying to "circumvent" these aesthetic "deviations" while the tank was evolving. However, I knew not to. I knew that the long-term gains from letting this system evolve would far exceed any "relief" I'd gain from siphoning out the biofilms, removing decomposing leaves, and clearing the water.

And, as usual- Nature delivered...because I didn't get in Her way.

We've done this numerous times with similar results. Inauspicious starts.

Botanical-method aquariums typically require more time to evolve than more "conventional" aquariums do. They are dependent upon the development of a specialized ecology, which includes fostering organisms like fungal growths and biofilms.This process can be "expedited" or manipulated a bit, but to achieve truly meaningful and beneficial results, you just can't rush stuff! 

You can't interrupt it, either.

When you do, as we've learned, results can be, well- "different" than they would be if you allow things to continue on at their own pace. Not necessarily always  "bad"- just not as good as what's possible if you relax and let Nature run Her course without interruption. Following a plan is never a bad idea; it can lead to some exciting destinations. 


However, the ability to "pivot" and "go with the flow" is really important, too.

It's not always a bad idea to switch things around if you're suddenly inspired to do so. What I hate to see is when hobbyists attempt to "intervene" on the processes which are occurring in the tank- like the recruitment of biofilms and fungal growths, the breakdown of leaves, etc. THAT'S a problem, imho.  You can change the "overall theme" without irrevocably interrupting Nature's processes.

Yeah, there IS a certain kind of "intervention" which I occasionally embrace myself. As I've previously discussed here, on occasion, I'll start to execute on an idea I've had, and very early (or sometimes, not so early) in the process, I'll completely lose interest in it for whatever reason (it can be anything from "not feeling it!" to "I hate that I can't hide that heater!"), and the desire to abort and move on to something else on my "to do list" beckons.

In general, however, I play a really long game.

One which acknowledges that the fact that our botanical-method aquariums evolve over very long periods fo time, not reaching the state that we perhaps envisioned for many months. My actions reflect this mindset. Unless there is some major emergency, about the only thing that I might do is to add a few more botanicals, re-arrange some wood, or just wait it out.

Of course, if you really are "not feeling it" (it happens!), does it mean tearing the whole thing apart and starting over?


You can change the "look" or aesthetic direction of an aquairum- fairly significantly- without disrupting its function.

One of the things I've done a lot in recent years when making big changes to aquariums is to keep the substrate layers from my existing tanks and "build on them."  It makes a ton of sense, really. Why waste this goodness, just because the "theme" of the "new" tank is different than the existing one?  

Your South American-themed tank won't be that much different if you change up the "hardscape" to turn it into s Southeast Asian-themed tank, while leaving the substrate layer intact, right?

In other words, I'm taking advantage of the well-established substrate layers, complete with their sediments, decomposing leaves and bits of botanicals, and simply building upon them with some additional substrate and leaves. I've done this many times over the years- and I'm sure a lot of you have, too-it's hardly a "game-changing" practice, but it's something not everyone talks about.

I believe that preserving and building upon an existing substrate layer provides not only some biological stability (ie; the nitrogen cycle), but it has the added benefit of maintaining some of the ecological diversity and richness created by the beneficial fuana and the materials present within the substrate. 

I know many 'hobby old timers" might question the safety- or the merits-of this practice, mentioning things like "disturbing the bacterial activity" or "releasing toxic gasses", etc. A lot of 'em would rather have you simply remove this stuff altogether. It's "all or nothing" for them! I'm not sure how leaving the substrate layer intact is problematic. It doesn't "die." I believe that particular belief is steeped in "aquarium mythology", conflates a lot of different ideas and topics, and has generally been misapplied and misunderstood over the years.

I simply have never experienced any issues of this nature from this practice. Well maintained systems generally are robust and capable of evolving from such disturbances. And we're not really "disturbing" the substrate when we preserve it, are we? Moving around a few pieces of wood or rock might cloud the water a bit, but it's not wholesale disturbance of the substrate.

I see way more benefits to this practice than I do any potential issues.

Since I tend to manage the water quality of my aquariums well, if I say so myself, I have never had any issues, such as ammonia or nitrite spikes, by doing this- in fresh or saltwater systems. It's a logical way of maintaining stability and continuity- even in an arguably disruptive and destabilizing time!

This idea of a "perpetual substrate"- keeping the same substrate layer "going" in successive aquarium iterations- is just one of those things I believe that we can do to replicate Nature in an additional way.


Well, think about it for just a second. In Nature, the substrate layer in rivers, streams, and yeah, flooded forests and pools tends to not completely wash away during wet/dry or seasonal cycles.

Oh sure, some of the material comprising the substrate layer may get carried away by currents or other weather dynamics, but for the most part, a good percentage of the material- and the life forms within it- remains when the water recedes. Wind and weather add additional materials to the now terrestrial environment, which become part of the aquatic habitat when the waters return.

So, by preserving the substrate from the previous iteration of your aquarium, and perhaps "refreshing" it a bit with some new materials (ie; sand, sediment, gravel, leaves, and botanicals), you're essentially mimicking some aspects of the way Nature functions in these wild habitats!

And, from an aquarium management perspective, consider the substrate layer a living organism (or "collective" of living organisms, as it were), and you're sure to look at things a bit differently next time you "re-do" a tank!

I suppose, one could view the process of "perpetuating" the substrate almost like persuing "eternal youth"- it's not entirely possible to achieve, but you can easily embrace the idea of renewal and continuity within your aquarium. It's a very natural process. Perhaps it's even beneficial in some way over the long term?

Things change in Nature, some things are utilized elsewhere, and other things are  preserved in situ. Nothing goes to waste.

Rather, stuff gets "folded" into the changing ecosystem. Leaves on the forest floor become a lush ecological niche for fungal growth and bacteria, and a grazing substrate for fishes when submerged. Tree branches become "attachment points" for epiphytic plants, sponges, and other aquatic life forms.

Nature is very efficient. We should take a cue from Her! "Disruption" is often a form of renewal and evolution in Nature.

Patience, as always, is the key ingredient here. Of course, this is a hobby, and it should be fun...and you should feel free to change stuff up if it's not. However, make it a point to consider your actions in the "big picture", and it takes on a greater significance.

You need to have an understanding that you're creating a dynamic environment, not simply an "aquascape." And it's constantly evolving- even when you're not ripping it apart!  It's anything but "static"-sort of like a planted aquarium, but in reverse (rather than plants growing, the botanicals are, for want of a better word "diminishing")! At any given time, you'll have materials like leaves in various states of decomposition, seed pods, slowly softening, breaking down, and recruiting biofilms and a "patina" of  fungal growth.

It begs the most fundamental of questions about our botanical method practice:

What happens over time in a botanical method aquarium? What changes occur along the way?

Well, typically, at its simplest, as most of you who've played with this stuff know, the botanicals will begin to soften and break down. Botanical materials are the very definition of the word "ephemeral." Nothing lasts forever, and botanicals are no exception! Pretty much everything we utilize- from Guava leaves to oak twigs- starts to soften and break down over time.

Most of these materials should be viewed as"consumables"- meaning that you'll need to replace them over time if you want maintain some environmental consistency. Again, perfectly analogous to what occurs in Nature.

You're not an "aquascaper" in the classic hobby sense when you play with these types of systems. Rather, you're a a sort of "superintendent" to Nature, helping Her do what she has done for eons. You're not simply an idle "passenger," either- you play an active role in conceiving, setting up, and maintaining such a system. You need to take some cues from Nature, and that often means simply standing by and observing as she does Her work and goes through Her process.

You learn. You evolve with your aquarium, on a very real level. 

Sometimes, it requires intervention on your part- at least in your own mind, perhaps. Other times, it simply involves sitting back, letting things unfold, and observing patiently.

Watching a display aquarium evolve and sort of "find itself" naturally over time is proving to be one of the most enjoyable discoveries I've made in the hobby in decades. It's a mindset that I actually had in my youth- by necessity, because I had very limited resources except for time- yet lost as I grew into adulthood and "evolved" in the hobby. With more skills and economic resources, I could "do more"- but the reality is that it wasn't always the right thing.

It took me a few decades after hitting so-called "advanced" hobbyist status before it really hit me that, by simply studying the function of natural ecosystems, all of the answers I needed to be successful as an aquarist were right there! I just needed to figure out which questions to ask.

I'm still deep in that process, decades later! 

By understanding that my aquariums are governed by the same "laws" which apply to natural aquatic ecosystems, and developing and following simple practices and husbandry routines to embrace this, and monitoring what's occurring in the tank (as opposed to constantly trying to intervene to "pre-empt" what we in the hobby have commonly perceived to be problems), I've personally had more beautiful, healthy and stable aquariums, and...more success than ever before.

Accepting that there is most definitely an elegant, yet complex ecological "dance" in our aquariums, and becoming an "active monitor" instead of an "active intervener" has added an enjoyable and rewarding aspect to my love of the hobby.

I think that this approach to the "dance" not only makes you a more engaged hobbyist, it gives you a remarkable appreciation for the long term evolution of an aquarium; an appreciation for the pace by which Nature operates, and the direction in which your aquarium ultimately goes.

By doing this, you get the enjoyment of seeing the "evolution" every day! Observing and enjoying the subtle nuances of your aquarium at every stage of its existence. With my "go slow" mindset and practice, the differences are subtle in the short term- the "payoffs" really more apparent over the longer term. 

Again, it's okay to make changes- even significant ones- to the "theme" of your aquarium. However, it's simply not good practice to interfere with the processes which allow it to become what Nature ( and YOU, too, if you're honest with yourself) wants it to become.

I know, it does feel a bit "yin" and "yang"- like I'm pulling from both sides- telling you, on one hand, that it's okay to make significant changes to a tank, while simultaneously urging you to deploy extreme patience and an almost "sit back and relax" approach...These seemingly diametrically opposite actions actually work really well together when you have the "common denominator" of good intentions, vision, careful actions, and an appreciation for what Nature can do if we let Her.

This philosophy, like so many things I ask you to consider here- doesn't always seem to make any sense.

Until it does.

Be kind to yourself- and to Nature.

Trust that She'll guide your aquarium effectively along the way to its ultimate potential. She won't let you down. Even if you take a slight detour now and again.

Stay confident. Stay observant. Stay curious. Stay patient....

And Stay Wet.


Scott Fellman

Tannin Aquatics 




For the love of weird substrates...

One of the "cornerstones" of our botanical-method aquarium practice is the use of substrate. Specifically, substrate materials which can influence- or make it easier to influence- water chemistry in the aquarium, as well as to help foster a "microbiome" of small organisms which will provide ecological diversity for the system.

Substrates, IMHO, are one of the most often-overlooked components of the aquarium. We tend to just add a bag of  "_____________" to our tanks and move on to the "more exciting" stuff like rocks and "designer" wood. It's true! Other than planted aquarium enthusiasts, the vast majority of hobbyists seem to have little more than a passing interest in creating and managing a specialized substrate or associated ecology.


A real pity, especially for those of us who are interested in botanical-method aquariums, which replicate natural aquatic habitats where soils and geology play a HUGE role in influencing the environmental parameters of these ecosystems. And in the hobby, we've largely overlooked the benefits and possibilities which specialized substrates can offer.

So I started to experiment with materials to recreate some of the characteristics of wild aquatic habitats which fascinated me. And an obsession was born.

I started playing with substrates mainly because I couldn't find exactly what I was looking for on the market. This is not some indictment of the major substrate manufacturers out there...I LOVE almost all of them and use and happily recommend ones that I like. I'm obsessed with substrates. I think that the companies which produce them are among the coolest of the cool aquatics industry brands. If I wasn't doing this botanical thing with Tannin, I'd probably have started a company that specializes in substrates for aquariums. Seriously.

And the fact is, the major manufacturers need to market products that more than like 8 people are interested in. It's unreasonable to think that they'd devote precious resources to creating a product that would be geared to such a tiny target. 

And of course, being one of those 8 people who are geeked-out about weird substrates, I decided that I'd "scratch my own itch" (as we did with the botanical thing..) and formulate and create some of my own. Thus, the NatureBase product line was born!

I realized that the specialized world which we operate in embraces some different ideas, unusual aesthetics, and is fascinated by the function of the environments we strive to replicate. These are important distinctions between what we are doing with substrates at Tannin, and what the rest of the aquarium hobby is doing.

Our NatureBase line is not intended to supersede or completely replace the more commonly available products out there as your "standard" aquarium substrate, because: a) they're more expensive, b) they're not specifically "aesthetic enhancements", c) they are not intended to be planted aquarium substrates, and d) because of their composition, they'll add some turbidity and tint to the aquarium water, at least initially (not everyone could handle THAT!)

So, right there, those factors have significantly segmented our target market...I mean, we're not trying to be the aquarium world's "standard substrate", they weren't formatted to grow aquatic plants, we're not marketing them just for the cool looks, and we can't emphasize enough that they will make your water a bit turbid when first submerged. If you have fishes which dig, or which like to "work" the substrate, you may see a near-continuous turbidity in your aquarium!

Oh, joy.

Those factors alone will take us out of contention for large segments of the market!

This is important to grasp.

I mean, these substrates are intended to be used in more natural, botanical-style/biotope-inspired aquariums. Our first two releases, "Igapo" and "Varzea", are specific to the creation of a type of "cyclical" terrestrial/aquatic feature. They do exactly what I wanted them to do, and they were specifically intended for use in specialized set ups, like the "Urban Igapo" idea we've been talking about for a long time here, as well as brackish water mangrove environments, etc.

Let's touch on the "aesthetic" part for a minute.

Most of our NatureBase substrates have a significant percentage of clays and sediments in their formulations. These materials have typically been something that aquarists have avoided, because they will cloud the water for a while, and often impart a bit of color. We also have some botanical components in a few of our substrates, because they are intended to be "terrestrial" substrates for a while before being flooded...and when this stuff is first wetted, some of it will float.

And that means that you're going to have to net it out, or let your filter take it out. You simply won't have that "issue" with your typical bag of aquarium sand!

Shit, you're probably just frothing right now, waiting to cloud and dirty up your aquariums with this stuff, huh?


I can't for the life of me figure out why not? ;)

Remember, some of these substrates were formulated for a very specific purpose: To replicate the terrestrial soils which are seasonally inundated in the wild. As such, these products simply won't look or act like your typical aquarium substrate materials!

Scared off completely yet? I hope not.

Why include sediments and clays in our mixes? 

Well, for one thing, sediments are an integral part of the natural substrates in the habitats from which our fishes come. So, they're integral to our line. In fact, I suppose you'd best classify NatureBase products as "sedimented substrates."

Think about this: Many of our favorite habitats are forest floors and meadows which undergo periodic flooding cycles in the Amazon, which results in the creation of aquatic habitats for a remarkable diversity of fish species.

Depending on the type of water that flows from the surrounding rivers, the characteristics of the flooded areas may vary. Another important impact is the geology of the substrates over which the rivers and streams pass. This results in differences in the physical-chemical properties of the water.

In the Amazon, areas flooded by rivers of black or clear waters, with acid pH and low sediment load, in addition to being nutritionally poor, are called “igapó."

The flooding often lasts for several weeks or even several months, and the plants and trees need special biochemical adaptations to be able to survive the lack of oxygen around their roots. We've talked about this a lot here over the years.


Forest floor soils in tropical areas are known by soil geologists as "oxisols", and have varying amounts of clay, sediments, minerals like quartz and silica, and various types of organic matter. So it makes sense that when flooded, these "ingredients" will have significant impact on the aquatic environment. This "recipe" is not only compositionally different than typical "off-the-shelf" aquarium sands and substrates- it looks and functions differently, too.


You CAN wet them right away; you don't have to do a "wet/dry season" igapo-style tank with them.  However, you should be ready for some cloudy water for a week or more! And again, if you have fishes which like to "work" the substrate, it will be a near-constant thing, the degree to which it will be is based on the habits of the fishes you keep.


And that's where a lot of people will metaphorically "leave the room."Turbid, darker water is a guaranteed "freak out" for a super-high  high percentage of aquarists. 

So, yeah, you'll have to make a mental shift to appreciate a different look and function.

And many hobbyists simply can't handle that. I've been extremely up front with this stuff since the introduction of these substrates, to ward off the, "I added NatureBase to my tank and it looks like a cloudy mess! This stuff is SHIT!" type of emails that inevitably come when people don't read up first before they purchase the stuff. (And trust me- the fact that you're even reading this blog, or listening to this podcast puts you in the tiniest minority of aquarium hobbyists!)

Let's talk a bit about how to "live" with these substrates. 

There are a lot of different ways to use these substrates in all sorts of tanks. I mean, if you want some of the benefits and want to geek out and experiment with them, you can use a "sand cap" of whatever conventional substrate you prefer on top, and likely limit the turbidity somewhat, much like the practice of aquarists who employ "dirted" substrates do.

Oh, and the plant thing...

We're asked a LOT if these substrates can grow aquatic plants. Now, although they were intended to facilitate the growth of terrestrial plants, like grasses, the fact is, both our customers and ourselves have seen pretty damn good plant growth in tanks using this stuff!

Our Igapo and Varzea substrates mimic sandy acidic soils that have a low nutrient content. And, as you know, the color and acidity of the floodwater is due to the acidic organic humic substances (tannins) that dissolve into it. The acidity from the water translates into acidic soils, which makes sense, right?

Now, I admit, I am NOT a geologist, and I'm not expert in soil science. I know enough to realize that, in order to replicate the types of habitats I am fascinated with, it required different materials. If you ask me, "Will this fish do well with this materials?" or, "Can I grow "Cryptocoryne in this?", or "Does this make a good substrate for shrimp tanks?" I likely won't have a perfect answer. Sorry.

Periodically, plant enthusiasts will ask me about the "cation exchange capacity" of our substrate. Cation Exchange Capacity (CEC) is the ability of a material to absorb positively-charged nutrient ions. This means the substrate will hold nutrients and make them available for the plant roots, and therefore, plant growth. CEC measures the amount of nutrients, more specifically, positivity changed ions, which a substrate can hold onto/store for future use by aquatic plants.

Thus, a "high CEC" is important to many aquatic plant enthusiasts in their work.  While it means that the substrate will hold nutrients and make them available for the plant roots. it doesn't indicate the amount of nutrients the substrate contains. 

For reference, scientists measure cation exchange capacity (CEC) in milliequivalents per 100 grams ( meq/100g).

To really get "down and dirty" to analyze substrates scientifically, CEC determinations are often done by a process called "Method 9081A of EPA SW- 846." What the....? CEC extractions are often also analyzed on ICP-OES systems. A rather difficult and pretty expensive process, with equipment and methods that are not something casual hobbyists can easily replicate!

As you might suspect, CEC varies widely among different materials. Sand, for instance, has a CEC less than 1 meq/100 g. Clays tend to be over 30 meq/100 g. Stuff like natural zeolites are around 100 meq/100g! Soils and humus may have CEC up to 250 meq/100g- that's pretty serious!

What nutrients are we talking about here? The most common ones which come into play in the context of CEC are iron, potassium, calcium and magnesium. So, if you're into aquatic plants, high CEC is a good thing!

Of course, this is where the questions arise around the substrates we play with.

It makes sense, right?

Our "Nature Base" substrates do contain materials such as clays and silts, which could arguably be considered "higher CEC" materials, because they're really fine- and because higher surface area generally results in a higher CEC. The more surface area there is, the more potential bonding sites there are for the exchange to take place. Alas, nothing is ever exactly what we hope it should be in this hobby, and clays are often not all that high in their CEC "ratings."

Now, the "Nature Base" substrates are what we like to call “sedimented substrates”, because they are not just sand, or pellets of fired clays, etc. They are a mix of materials, and DO also have some terrestrial soils in the mix, too, which are also likely higher in CEC. And no, we haven't done CEC testing with our substrates...It's likely that in the future, some enthusiastic and curious scientist/hobbyist might just do that, of course!

Promising, from a CEC standpoint, I suppose!

However, again, I must emphasize that they were really created to replicate the substrate materials found in the igapo and varzea habitats of South America, and the overall habitat- more "holistically conceived"-not specifically for plant growth. And, in terrestrial environments like the seasonally-inundated igapo and varzea, nutrients are often lost to volatilization, leaching, erosion, and runoff..

So, it's important for me to make it clear again that these substrates are more representative of a terrestrial soil. Interestingly, the decomposition of detritus and leaves and such in our botanical-method aquariums and "Urban Igapo" displays is likely an even larger source of “stored” nutrients than the CEC of the substrate itself, IMHO. Thus, they will provide a home for beneficial bacteria- breaking down organics and helping to make them more available for plant growth. 

Perhaps that's why aquatic plants grow so well in botanical-method aquariums?

Yeah, the stuff DOES grow aquatic and riparian plants and grasses quite well, in our experience! Yet, again- I would not refer to them specifically as "aquatic plant substrates." They're not being released to challenge or replace the well-established aquatic plant soils out there. They're not even intended to be compared to them!

Remember, our "Igapo" and "Varzea" substrates are intended to start out life as "terrestrial" materials, gradually being inundated as we bring on the "wet season." And because of the clay and sediment content of these substrates, you'll see some turbidity or cloudiness in the water. It won't immediately be crystal-clear- just like in Nature. That won't excite a typically planted aquarium lover, for sure. 

I can't stress it often enough: With our emphasis on the "wholistic" application of our substrate, our focus is on the "big picture" of these closed aquatic ecosystems.

I'll be the first to tell you that, while I have experimented with many species of plants, inverts, and fishes with these substrates, I can't tell you that every single fish or plant will like them. You'll simply have to experiment!

Well, shit- that's not something that you typically hear an aquarium hobby brand tell you to do with their products every day, huh? Like, I'm not going to make all sorts of generalized statements about everything I think that these products can do. It would be very unhelpful. I'd rather focus on how they perform in the types of systems in which they were intended to work in, and what the possible downsides could be!

The whole point here is that these substrates are perfect for a whole range of applications. They're not "the greatest substrates ever made!" or anything like that. However, they are super useful for replicating the soils of some of our favorite aquatic habitats. 

And for doing some of those geeky experiments that we love so much. So, that pretty much covers the "sedimented" substrate thing for now. Let's talk about "alternative" substrates for a bit...


In my experience, and in the reported experiences from hundreds of aquarists who play with botanical materials breaking down in and on their aquariums' substrates, undetectable nitrate and phosphate levels are typical for this kind of system. When combined with good overall husbandry, it makes for incredibly stable systems.

I've been thinking through further refinements of the "deep botanical bed"/sand substrate relationship. I've been spending a lot of time researching natural aquatic systems and contemplating how we can translate some of this stuff into our closed system aquaria.

Now, I realize, when contemplating really deep aggregations of substrate materials in the aquarium, that we're dealing with closed systems, and the dynamics which affect them are way different than those in Nature, for the most part.

And I realize that experimenting with these unusual approaches to substrates requires not only a sense of adventure, a direction, and some discipline- but a willingness to accept and deal with an entirely different aesthetic than what we know and love. And this also includes pushing into areas and ideas which might make us uncomfortable, not just for the way they look, but for what we are told might be possible risks.

One of the things that many hobbyists ponder when we contemplate creating deep, botanical-heavy substrates, consisting of leaves, sand, and other botanical materials is the possible buildup of hydrogen sulfide, CO2, and other undesirable compounds within the substrate.

Well, it does make sense that if you have a large amount of decomposing material in an aquarium, that some of these compounds are going to accumulate in heavily-"active" substrates. Now, the big "bogeyman" that we all seem to zero in on in our "sum of all fears" scenarios is hydrogen sulfide, which results from bacterial breakdown of organic matter in the total absence of oxygen.

Let's think about this for just a second.

In a botanical bed with materials placed on the substrate, or loosely mixed into the top layers, will it all "pack down" enough to the point where there is a complete lack of oxygen and we develop a significant amount of this reviled compound in our tanks?  I just don't think so. I think that we're more likely to see some oxygen in this layer of materials, and I can't help but speculate- and yeah, it IS just speculation- that actual de-nitirifcation (nitrate reduction), which lowers nitrates while producing free nitrogen, might actually be able to occur in a "(deep) botanical" bed.

And it's certainly possible to have denitrification without dangerous hydrogen sulfide levels. As long as even very small amounts of oxygen and nitrates can penetrate into the substrate, this will not become an issue for most systems. I personally have yet to see a botanical-method aquarium where the material has become so "compacted" as to appear to have no circulation whatsoever within the botanical layer.

Now, sure, I'm not a scientist, and I base this on the management of, and close visual inspection of numerous aquariums, as well as the basic chemical tests I've run on my systems under a variety of circumstances. As one who has made it a point to keep my botanical-method aquariums in operation for very extended time frames, I think this is significant. The "bad" side effects we're talking about should manifest over these longer time frames...and they just haven't.

And then there's the question of nitrate. 

Although not the terror that ammonia and nitrite are known to be, nitrate accumulation is something a lot of hobbyists are concerned with. As nitrate accumulates, fish will eventually suffer some health issues. Ideally, we strive to keep our nitrate levels no higher than 5-10ppm in our aquariums.  

As a reef aquarist, I was always of the "...keep it as close to zero as possible." mindset, until I realized that corals just grow better with the presence of some nitrate! This was especially evident in my large scale coral grow-out raceways.

It seems that 'zero" nitrate is not always the most realistic or achievable target in a heavily-botanical-laden aquarium, although I routinely see undetectable nitrate reading in my tanks. You have a bit more "wiggle room", IMHO, however, before concern over fish health is a factor. Now, when you start creeping towards 50ppm, you're getting closer towards a number that should alert you.

It's not a big "stretch" from 50ppm to more potentially detrimental readings of 75ppm and higher...

And then you get towards the range where health issues could manifest themselves in your fishes. Now, many fishes will not show any symptoms of nitrate poisoning until the nitrate level reaches 100 ppm or more. However,  studies have shown that long-term exposure to moderate concentrations of nitrate stresses fishes, making them more susceptible to disease, affecting their growth rates, and inhibiting spawning in many species. 

At those really high nitrate levels, fishes will become noticeably lethargic, and may have other health issues that are obvious upon visual inspection, such as open sores or reddish patches on their skin. And then, you'd have those "mysterious deaths" and the sudden death (essentially from shock) of newly-added fishes to the aquarium, because they're not acclimated to the higher nitrate concentrations.

Okay, that's scary stuff. However, high nitrate concentrations are not only manageable- they're something that's completely avoidable in our aquairums.

Quite honestly, even in the most heavily-botanical-laden systems I've played with, I have personally never seen a higher nitrate reading than around 5ppm. Often, as I mentioned above, they're undetectibIe on hobby-level test kits. I attribute this to common sense stuff: Good quality source water (RO/DI), careful stocking, feeding, good circulation, not disturbing the substrate, and consistent basic aquarium husbandry practices (water exchanges, filter maintenance, etc.).

Now, that's just me.

I'm no scientist, certainly not a chemist, but I have a basic understanding of maintaining a healthy nitrogen cycle in the aquarium. And I am habitual-perhaps even obsessive- about consistent maintenance. Water exchanges are not a "when I get around to it" thing in my aquarium management "playbook"- they're "baked in" to my practice.

So yeah, although nitrate is something to be aware of in botanical-method aquariums, it's simply not an ominous cloud hanging over our success.

Relatively shallow sand or substrate beds seem to be optimal for denitrification, and many of us employ them for the aesthetics as well. Light "stirring" of the top layers, if you're concerned about any potential "dead spots" is something that is permissible, IMHO. Any debris stirred up can easily be removed mechanically by filtration, as mentioned above.

But that's it.


Of course, as we already discussed, you don't have to go crazy siphoning the shit (literally!) out of your sand every week, essentially decimating populations of beneficial microscopic infauna -or interfering with their function- in the process.

What I am starting to feel more and more confident about is postulating that some form of denitrification occurs in a system with a layer of leaves and botanicals as a major component of the tank.

Now, I know, I have little rigorous scientific information to back up my theory, other than anecdotal observations and even some assumptions. However, there is always an example to look at- Nature. 

Of course, Nature and aquariums differ, one being a closed system and the other being "open." However, they both are beholden to the same laws, aren't they? And I believe that the function of the captive leaf litter bed and the wild litter beds are remarkably similar to a great extent.

The thing that fascinates me is that, in Nature, leaf litter beds perform a similar function; that is, fostering biodiversity, nutrient export, and yes- denitrification. Let's take a little look at a some information I gleaned from the study of a natural leaf litter bed for some insights.

In a slow-flowing wild Amazonian stream with a very deep leaf litter bed, observations were made which are of some interest to us. First off, oxygen saturation was 6.7 3 mg/L (about 85% of saturation), conductivity was 13.8 microsemions, and pH was 3.5.

Some of these parameters (specifically the very low pH) are likely difficult to obtain and maintain in the aquarium, but the interesting thing is that these parameters were stable throughout a months-long investigation.

Oxygen saturation was surpassingly low, given the fact that there was some water movement and turbulence when the study was conducted. The researchers postulated that the reduction in oxygen saturation presumably reflects respiratory consumption by the organisms residing in the litter, as well as low photosynthetic generation (which makes sense, because there is no real algae or plant growth in the litter beds).

And of course, such numbers are consistent with the presence of a lot of life in the litter beds.




Microscopic investigation confirmed that the leaf litter was heavily populated with fungi and other microfauna. There was also a significant amount of fish life. Interestingly, the fish population was largely found in the top 12"/30cm of the litter bed, which was estimated to be about 18"/45cm deep. The food web in this type of habitat is comprised largely of fungal and bacterial growth which occurs in the decomposing leaf litter. 

Okay, I"m throwing a lot of information here, and doing what I hope is a slightly better-than-mediocre attempt at tying it all together. The principal assertions I'm making are that, in the wild, the leaf litter bed is a very productive place, and has a significant impact on its surroundings, and that it's increasingly obvious to me that many of the same functions occur in an aquarium utilizing leaf litter and botanicals.

"Enriching" a substrate with botanicals, or composing an entire substrate of botanicals and leaves is a very interesting and compelling subject for investigation by hobbyists.

So, three areas of potential investigation for us:

*Use of botanicals and leaves to comprise a "bed" for bacterial growth and denitrification.

*Understanding the chemical/physical impact of the botanical "bed" on an aquarium. (ie, pH, conductivity, etc.)

*Utilization of a botanical bed to create a supplemental food source for the resident fishes.

We've also touched on the idea of a leaf litter/botanical bed as "nursery" for fry, something more and more hobbyists/breeders are confirming is a logical "go-to" thing for them. 

Interesting semi-anecdotal observations from my friends in the know suggest that the biofilms for decaying leaves form a valuable secondary food for the fry of fishes such as Discus, Uaru, (after they’re done feeding on their parent’s exuded slime coat) and even Loricariid catfishes. And I've seen juvenile fishes  of a variety of species "appear" from my botanical-rich aquariums over the years, fat and happy, apparently deriving some nutrition from the fungi, bacteria, and small crustaceans which live in, on, and among the leaf litter bed.

My own experience with creating leaf-litter-bed-focused aquariums has proven that supplemental food production for the resident fishes is a real "thing" that we need to consider. It's a valid and very exciting approach to creating a functional closed aquatic ecosystem.


We talk about the concept of "substrate enhancement" or "enrichment" a lot in the context of aquatic botanicals (we tend to use the two terms interchangeably).

Again, we're not talking about "enrichment" in the same context as say, planted aquarium guys, with materials put into the substrate specifically for the benefit of plants. However, the addition of botanical and other materials CAN create a sort of organic "mulch" which benefits many aquatic plants! 

Rather, "enrichment" in our context refers to the addition of botanical materials for creating a more natural-appearing, natural-functioning substrate- one which provides a haven for microbial life, as well as for small crustaceans, biofilms, and even algae, to serve as a foraging area for our fishes and invertebrates.

We've found over the years of playing with botanical materials that substrates can be really dynamic places, and benefit from the addition of leaves and other materials. For many years, substrates in aquarium were really just sands and gravels. With the popularity of planted aquariums, new materials, like soils and mineral additives, entered into the fray.

With the botanical-method aquarium starting to gain in popularity, now you're seeing all sorts of materials added on and in the substrate...for different reasons of course.

I think the big takeaway is that we should not be afraid to experiment with the idea of mixing various botanical materials into our substrates, particularly if we continue to embrace solid aquarium husbandry practices.

In my opinion, richer, botanically-enhanced substrate provides greater biological diversity and stability for the closed system aquarium. 

Is it for everyone?

Not for those not willing to experiment and be diligent about monitoring and maintaining water quality. Not for those who are superficially interested, or just in it for the unique aesthetics it affords. 

However, for those of you who are adventurous, experimental, diligent, and otherwise engaged with managing and observing your aquariums, I think it offers amazing possibilities. Not only will you gain some fascinating insights and the benefits of "on-board" nutrient export/environmental "enrichment"- you will also get the aesthetics of a more natural-looking substrate as well.

Like so many things we do in our niche, the "weird" alternative and botanical-enriched substrate approaches are fascinating, dynamic, and potentially ground-breaking for the aquarium hobby. For the adventurous, diligent, and observant aquarist, they present numerous opportunities to learn, explore, and create amazing, function-first aquatic ecosystems.

Who's in?

Stay creative. Stay observant. Stay diligent. Stay thoughtful...

And Stay Wet.


Scott Fellman

Tannin Aquatics