What's the big deal about substrates?

Of all the fun topics in botanical-style aquarium keeping, few hold my interest as much as substrates.

I imagine the substrate as this magical place which fuels all sorts of processes within our aquariums, and that Nature tends to it in the most effective and judicious manner. 

Yeah, I'm a bit of a "substrate romantic", I suppose.😆

Particularly in transitional habitats, like flooded forests, etc. the composition and characteristics of the substrate plays a huge role in the ecology of the aquatic habitat. The presence of a lot of soils, clays, and sediments in these substrates, as opposed to just sand, creates a habitat which provides a lot of opportunity for organisms to thrive.

The substrates are not just "the bottom." 

They are diverse harbors of life, ranging from fungal and biofilm mats, to algae, to epiphytic plants. Decomposing leaves, seed pods, and tree branches compose the substrate for a complex web of life which helps the fishes we're so fascinated by to flourish. And, if you look at them objectively and carefully, they are beautiful.

Detritus ("Mulm") located in the sediments is the major source of energy and/or nutrients for many of these dynamic aquatic habitats. The bacteria which perform all the important chemical reactions, such as converting ammonia to nitrite, nitrates to nitrogen, releasing bound-up nutrients, neutralizing hydrogen sulfide, etc. will obtain  essential nutrients from the detritus (this is what autotrophic bacteria that metabolize ammonia/ammonium or hydrogen sulfide for energy do).

These bacteria may also "harvest" those nutrients, as well as metabolize (aerobically or anaerobically) the organic compounds present in the detritus for energy, just like heterotrophs do.

The processing of nutrients in the aquarium is a fascinating one; a real "partnership" between a wide variety of aquatic organisms.

Yes, there is a lot of amazing biological function occurring in these layers. And of course, fostering this dynamic in the aquarium is one of the things we love the most. It's all part of our vision for the modern, botanical-style aquarium.

Now, hobbyists have played with deep sand beds and mixes of various materials in aquariums for many years, and knowledgable proponents of natural aquarium management, such as Diane Walstad, have discussed the merits of such features in far more detail, and with a competency that I could only dream of! That being said, I think the time has never been better to experiment with this stuff!

Again, we're talking about utilizing a wider variety of materials than just sand, so the dynamics are quite different, offering unique functions, processes, and potential benefits.

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

Before we talk about the actual substrate materials again, let's think about the processes that we would like to foster in a substrate, and the potential negatives that may be of concern to those of us who play with botanicals in our substrate configurations

 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 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 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 have yet to see a botanical-style 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 close visual inspection of numerous aquariums, and 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-style 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.

We need to look at substrates literally as an aquatic organism. And, like aggregations of organisms, they may be diverse, both morphologically and ecologically. They're a dynamic, functional part of the miniature ecosystems we create in our aquariums. We've used the "basic" stuff for a generation. It's time to open up our minds to a few new ideas. To rethink substrate. To reconsider why we incorporate substrate, and what we use.

What kinds of materials can we employ to create more "functional" substrates (which just happen to look cool, too?). What kinds of functions and benefits can we hope to recreate in the confines of our aquariums?


First off, think beyond just sands...or anything resembling "conventional" aquarium substrate. Think about what goes on in the benthic (bottom) regions in the natural habitats we love, and what benefits or support the materials which aggregate there provide for the organisms within the ecosystem.

Understand that the substrate is a dynamic, extremely important part of the aquarium, too. And what we construct our substrate with, and how we manage it, is of profound importance to our fishes!

Fostering fungal growth, as well as other microorganisms and small crustaceans, should be a huge component of the "why" we do this. These organisms, as we've discussed repeatedly, form a part of the "food chain" within our captive ecosystems, and offer huge benefits to the aquarium not only as potential supplemental nutrition for fishes, but as a means to process and export nutrients from within the botanical-style aquarium.


So, yeah, in summary- the substrate plays a huge role in the function of a botanical-style aquarium. We can create a "facility" with substrate materials which provides not only unique aesthetics- it provides priceless benefits: Production of supplemental nutrition for our fishes, and nutrient processing via a self-generating population of creatures that compliment, indeed, create the biodiversity in our systems on a more-or-less continuous basis.

True "functional aesthetics!"

A combination of finely crushed leaves, bits of botanicals, small twigs, etc. can form the basis for a more "biologically active" and even productive substrate. As these materials break down, they are colonized by fungi and biofilms, and impart  tannins, lignin, and other sources of carbon into the water to fuel a variety of microbial growth. 

As you might have gathered by now, we are an advocate of some rather "unconventional" substrate materials, particularly a classification what we call "Sedimented Substrates." 

Yeah, that'd be ours. NatureBase "Igapo", "Varzea", and the upcoming "Mangal", "Floresta" and "Selagor", are examples of substrates which have a lot of sediments and clays in their formulation. These substrates realistically replicate the composition, function, and look of soils which are found in many tropical aquatic habitats.

In fact, 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. Like, that's a problem? 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!

You can mix them with any of the above-mentioned commercially-available sands, or use them alone. You can gradually add water (as in our "Urban Igapo" concept), or simply fill your tank form day one. Expect significant cloudiness for several days as the materials settle out, though. Don't rinse these substrates...just put them to work right away.

Now, although you can (and should) play with these substrates "wet" from the start, I'd be remiss if I didn't remind you again that the igapo and varzea substrates were initially intended to be "terrestrial" for a period of time, to get the grasses and plants going, and then inundated.  

And of course, I'll tell you once again that immediately inundating a sediment-and-clay-heavy substrate can result in cloudiness. Just like in Nature. And it'll pass after a few days.


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. We've been up front with this stuff since these products were released, 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 the warning and mental shift indoctrinations have worked. No one has freaked out.

Instead, we're hearing how incredibly natural these aquariums look, and how the biological diversity and stability of these tanks are.

What goes on in an aquarium with sediments, botanicals- or leaves, in this instance as the total  "substrate" or "hardscape", as the case may be, is that they become the basis for biological activity in the tank. As we have discussed a million times here, as botanicals break down, they recruit bacteria, fungi, and other organisms on their surfaces.

That's the "big deal" about substrates.

Mix it up. Play with sediments, crushed leaves, broken bits of botanicals..All sorts of natural "stuff" which would previously have been considered "dirty" and "bad for long term maintenance" in almost anyone's book. Look at the advantages that can be realized, instead of the potential risks involved in experimenting.

Open your mind up to accept the look and function- and the "aesthetic challenges" of using non-traditional materials in your substrates. 

Stay creative. Stay excited. Stay bold. Stay studious...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



One of the things that drives most hobbyists crazy is when "stuff" gets blown around, covered or moved about in the aquarium. It can be because of strong current, the activity of fishes, or simply overgrown by plants. I understand the annoyance that many hobbyists feel; I recall this same aggravating feeling in many reef tanks where I had high flow and sand on the bottom- almost always a combination for annoyance! 

I mean, I get it. We have what feel is a carefully thought-out aquascape, looking exactly how we expected it would after setup. Yet, despite our ideas and thoughts, stuff moves around in the aquarium. It's something we can either accept, or modify in our aquariums, depending upon our preferences.


Yet, movement and "covering" of various materials by sediments, biofilms, etc., which accumulate on the substrate in natural habitats are everyday occurrences, and they help forge a very dynamic ecosystem. And they are constantly creating new opportunities for the fishes which reside in them to exploit.  

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 leaves, branches, seed pods, and the like.

Larger, more "hefty" materials, such as branches, 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.

A "dam", of sorts, if you will.

And this creates known structures within streams in areas like Amazonia, which are known to have existed for many years. Semi-permanent aquatic features within the streams, which influence not only the physical and chemical environment, but the very habits and abundance of the fishes which reside there.

Most of the small stuff, like leaves, tend to move around quite a bit... One might say that the "material changes" created by this movement of materials can have significant implications for fishes. As we've talked about before, they follow the food, often existing in, and subsisting off of what they can find in these areas.

New accumulations of leaves, detritus, and other materials benefit the entire ecosystem.

In the case of our aquariums, this "redistribution" of material can create interesting opportunities to not only switch up the aesthetics of our tanks, but to provide new and unique little physical areas for many of the fishes we keep.

And yeah, the creation of new feeding opportunities for life forms at all levels is a positive which simply cannot be overstated! As hobbyists, we tend to lament changes to the aquascape of our tanks caused by things outside of our control, and consider them to be a huge inconvenience, when in reality, they're not only facsimile of very natural dynamic processes-they are fundamental to their evolution.

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 adapting to a changing environment. And perhaps...maybe...the idea of fishes sort of having to constantly adjust to a changing physical 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..." Perhaps something which triggers 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 add new pieces from time to time.

Again, just like Nature.

We just need to "get over ourselves" on this aesthetic thing!

Another mental shift? Yeah, it is. An easy one, but one that we need make, really.

Like any environment, botanical/ leaf litter beds have their own "rhythm", fostering substantial communities of fishes. The dynamic behind this biotope can best be summarized in this interesting excerpt from an academic paper on blackwater leaf-litter communities by biologist Peter Alan Henderson, that is useful for those of us attempting to replicate these communities in our aquaria:

"..life within the litter is not a crowded, chaotic scramble for space and food. Each species occupies a sub-region defined by physical variables such as flow and oxygen content, water depth, litter depth and particle size…

...this subtle subdivision of space is the key to understanding the maintenance of diversity. While subdivision of time is also evident with, for example, gymnotids hunting by night and cichlids hunting by day, this is only possible when each species has its space within which to hide.”

In other words, different species inhabit different sections of the leaf litter beds. As aquarists, we should consider this when creating and stocking our botanical-style aquariums.

It  just makes sense, right?


So, when you're attempting to replicate such an environment, consider how the fishes would utilize each of the materials you're working with. For example, leaf litter areas would be an idea shelter for many juvenile fishes, catfishes, and even young cichlids to shelter among.

Submerged branches, larger seed pods and other botanicals provide territory and areas where fishes can forage for macrophytes (algal growths which occur on the surfaces of these materials). Fish selection can be influenced as much by the materials you're using to 'scape the tank as anything else, when you think about it!

And it's not just fishes, of course. It's a multitude of life forms.

There are numerous life forms which are found on ad among these materials as well, such as fungal growths, bacterial biofilms, etc. which we likely never really consider, yet are found in abundance in nature and in the aquarium, and perform vital roles in the function of the aquatic habitat.

Perhaps most fascinating  and rarely discussed in the hobby, are the unique freshwater sponges, from the genus Spongilla. Yes, you heard. Freshwater sponges! These interesting life forms attach themselves to rocks and logs and filter the water for various small aquatic organisms, like bacteria, protozoa, and other minute aquatic life forms. Some are truly incredible looking organisms!

(Spongilla lacustris Image by Kirt Onthank. Used under CC-BY SA 3.0)

Unlike the better-known marine sponges, freshwater sponges are subjected to the more variable environment of rivers and streams, and have adapted a strategy of survival. When conditions deteriorate, the organisms create "buds", known as  "gemmules", which are an asexually reproduced mass of cells capable of developing into a new sponge! The Gemmules remain dormant until environmental conditions permit them to develop once again!

Oh, cool!

To my knowledge, these organisms have never been intentionally collected for aquariums, and I suspect they are a little tricky to transport (despite their adaptability), just ike their marine cousins are. One species, Metania reticulata, is extremely common in the Brazilian Amazon. They are found on rocks, submerged branches, and even tree trunks when these areas are submerged, and remain in a dormant phase in the aforementioned gemmules during periods of desiccation!

Now, I'm not suggesting that we go and collect  freshwater sponges for aquarium use, but I am curious if they occur as "hitchhikers" on driftwood, rocks or other materials which end up in our aquariums. When you think about how important sponges are as natural "filters", one can only wonder how they might perform this beneficial role in the aquarium as well!

We've encountered them in reef tanks for many years...I wonder if they could ultimately find their way into our botanical-style aquariums as well?  Perhaps they already have. Have any of you encountered one before in your tanks?

The big takeaway from all of this: A botanical bed in our aquariums and in Nature is a physical structure, ephemeral though it may be- which functions just like an aggregation of branches, or a reef, rock piles, or other features would in the wild benthic environment, although perhaps even "looser" and more dynamic.

Stuff gets redistributed, covered, and often breaks down over time. Exactly like what happens in Nature.

Think about the possibilities which are out there, under every leaf. Every sunken branch. Every root. Every rock.

It's all brought about by the dynamic process of movement.

Perhaps instead of looking at the movement of stuff in our tanks as an annoyance, we might enjoy it a lot more if we look at it as an opportunity! An opportunity to learn more about the behaviors and life styles of our fishes and their ever-changing environment.

Stay observant. Stay creative. Stay excited. Stay open-minded...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




The slow(er) road to success with fish stocking...

One of the questions which we are asked less and less these days is, 'What kinds of fishes are suitable for a botanical-style aquarium?" I think that after 6 years of pounding all of these ideas into your heads about all of the strange nuances of botanical-style aquariums, it's almost universally understood that pretty much any fishes can live in them.

On the other hand, when it comes to how we stock our tanks, nothing has really changed...however, it could. And it should, IMHO.

We spend a pretty good amount of time studying, scheming, and pondering how to create a compatible, interesting, and attractive community of fishes within our aquariums.

It's probably among the most enjoyable things that we do in the hobby, right?

As a somewhat eccentric philosopher of all things fish, one of my favorite things to ponder is stuff that we do while creating our aquariums which is- intentionally or otherwise- analogous to the factors in Nature that result in the environments and fish populations that we find so compelling.

If you're like me, you likely spend a little too much time pondering all sorts of arcane aspects of the hobby...Okay, so maybe you're NOT like me, but you probably have a rather keen interest in the way Nature operates in the wild aquatic systems of the world, and stock your aquariums accordingly.

As one who studies a lot of details about some of the habitats from which our fishes come, I can't help but occasionally wonder exactly what it is that brings fishes to a given location or niche within a environment?

Now, the first answer we're likely to proffer is the most apparent...right? I mean, they follow the food!

Fishes tend to move into new areas in search suitable food sources as part of their life cycle. And food sources often become available in habitats such as flooded forest areas after the rains come, when decomposing leaves and botanical materials begin to create (or re-activate, as the case may be) "food webs", attracting ever more complex life forms into the area.

When we create our aquariums, we take into consideration a lot of factors, ranging from the temperament and size of our fish selections, to their appearance, right? These are all important factors. However, have you ever considered what the factors are in nature which affect the composition of a fish community in a given habitat?

Like, why "x" fish is living in a particular habitat?

What adaptations has the fish made that make it uniquely suitable for this environmental niche? Further, have you thought about how we as hobbyists replicate, to some extent, the actual selection processes which occur in Nature in our quest to create the perfect community aquarium?

Now, if you're an African Cichlid lover or reef hobbyist, I'm sure you have!

Social hierarchies, spatial orientations, and allopathic processes are vital to success in those types of aquariums; you typically can't get away with just throwing in a random fish or coral and hoping it will just mix perfectly.

However, for many hobbyists who aim to construct simple "community tanks", it isn't that vital to fill specific niches and such...we probably move other factors to the forefront when thinking about possible additions to our community of fishes: Like, how cool the fish looks, how large it grows, if it has a peaceful temperament, etc. More basic stuff.

However, in the end, we almost always make selections based upon factors which we deem important...again, a sort of near-mimicry of natural processes- and how the fishes work in the habitat we've created for them.

"Unnatural selection?" Or...Is it essentially what nature's does for eons?

Oh, and what exactly is an "aquatic habitat", by the way? In short, you could say that an aquatic habitat is the physical, chemical, and biological characteristics which determine the suitability for habitation and reproduction of fishes.

Of course, these characteristics can determine which fishes are found in a given area in the wild- pretty much without exception. It's been happening for eons.

Approaching the stocking of an aquarium by determining which fishes would be appropriate for the physical characteristics of the tank is not exactly groundbreaking stuff.

However, when we evaluate this in the context of "theme", and what fish would be found within, say, an Amazonian Igarape stream or a Southeast Asian peat swamp, the idea of adding fishes to "exploit" the features of the habitat we've created is remarkably similar to the processes which occur in Nature that determine what fish are found there, and it's the ultimate expression of good tank planning, IMHO.

It's just kind of interesting to think about in that context, right?

Competition is another one of the important factors in determining  how fish populations in the wild. Specifically, competition for space, resources (e.g.; food) and mates are prevalent. In our aquariums, we do see this to some extent, right? The "alpha male" cichlid, the Pleco that gets the best cave, and the Tetra which dominates his shoal.

How we create the physical space for our fishes can have significant impact on this behavior. When good hiding spaces are at a premium, as are available spawning partners, their will be some form of social hierarchy, right?

Other environmental factors, such as  water movement, dissolved oxygen, etc. are perhaps less impactful on our community once the tank is established. However, these factors figure prominently in our decisions about the composition of, or numbers or fishes in the community, don't they?

For example, you're unlikely to keep Hillstream loaches in a near stagnant, blackwater swamp biotope aquarium, just like you'd be unlikely to keep Altum Angelfish in a fast-moving stream biotope representation. And fishes which shoal or school will, obviously, best be kept in numbers.

"Aquarium Keeping 101", again.

One factor that we typically don't have in our aquaria is predation. I know very few aquarists who would be sadistic enough to even contemplate trying to keep predators and prey in the same tank, to let them "have at it" and see what happens, and who comes out on top!

I mean, there is a lot to this stuff, isn't there?

Again, the idea of creating a tank to serve the needs of certain fishes isn't earth-shattering. Yet, the idea of stocking the tank based on the available niches and physical characteristics is kind of a cool, educational, and ultimately very gratifying process. I just think it's truly amazing that we're able to actually do this these days.

And the sequence that you stock your tank in is extremely pertinent.

I think that you could literally create a sort of "sequence" to stocking various types of fishes based on the stage of "evolution" that your aquarium is in, although the sequence might be a bit different than Nature in some cases. For example, in a more-or-less brand new aquarium, analogous in this case to a newly-inundated forest floor, their might be a lot less in the way of lower life forms, such as fungi and bacteria, until the materials begin breaking down. You'd simply have an aggregation of fresh leaves, twigs, seed pods, soils, etc. in the habitat.

So, if anything, you're likely to see fishes which are much more dependent upon  allochthonous input...food from the terrestrial environment. This is a compelling way to stock an aquarium, I think. Especially aquarium systems like ours which make use of these materials en masse.

Right from the start (after cycling, of course!), it would not be unrealistic to add fishes which feed on terrestrial fruits and botanical materials, such as Colossoma, Arowanna, Metynis, etc. Fishes which, for most aquarists of course, are utterly impractical to keep because of their large adult size and/or need for physical space!

(Pacu! Image by Rufus46, used under CC BY-SA 3.0)

Now, a lot of smaller, more "aquarium suited" fishes will also pick at these fruits and seeds, so you're not totally stuck with the big brutes if you want to go this route! Interestingly, the consumption and elimination of fruits by fishes is thought to be a major factor in the distribution of many plants in the region.

Do a little research here and you might be quite surprised about who consumes what in these habitats!

More realistically for most aquarists, I'd think that you could easily stock first with fishes like surface-dwelling (or near surface-dwelling) species, like hatchetfishes and some Pencilfishes, which are largely dependent upon terrestrial insects such as flies and ants, in Nature. In other words, they tend to "forage" or "graze" little, and are more opportunistic, taking advantage of careless insects which end up in the water of these newly-inundated environs.

I've read studies where almost 100 species were documented which feed near-exclusively on insects and arthropods from terrestrial sources in these habitats! As I mention often, if you dive a bit deeper than the typical hobbyist writings, and venture into scholarly materials and species descriptions, you'll be fascinated to read about the gut-content analysis of fishes, because they give you a tremendous insight about what to feed in the aquarium!

Continuing on, it's easy to see that, as the environments evolve, so does the fish population. And the possibilities for simulating this in the aquarium are many and are quite interesting!

Later, as materials start to decompose and are acted on by fungi and bacteria, you could conceivably add more of the "grazing" type fishes, such as Plecos, small Corydoras, Headstanders, etc.

As the tank ages and breaks in more, this would be analogous to the period of time when micro-crustaceans and aquatic insects are present in greater numbers, and you'd be inclined to see more of the "micropredators" like characins, and ultimately, small cichlids.

Interestingly, scientists have postulated that evolution favored small fishes like characins in these environments, because they are more efficient at capturing small terrestrial insects and spiders in these flooded forests than the larger fishes are!

And it makes a lot of sense, if you look at it strictly from a "density/variety" standpoint- lots of characins call these habitats home!

Then there are detritivores.

The detrivorus fishes remove large quantities of this material from submerged trees, branches, etc. Now, you might be surprised to learn that, in the wild, the gut-content analysis of almost every fish indicates that they consume organic detritus to some extent! And it makes sense...They work with the food sources that are available to them!

At different times of the year, different food sources are easier to obtain.

And, of course, all of the fishes which live in these habitats contribute to the surrounding forests by "recycling" nutrients locked up in the detritus. This is thought by ecologists to be especially important in blackwater inundated forests and meadows in areas like The Pantanal, because of the long periods of inundation and the nutrient-poor soils as a result of the slow decomposition rates.

All of this is actually very easy to replicate, to a certain extent, when stocking our aquaria. Why would you stock in this sort of sequence, when you're likely not relying on decomposing botanicals and leaves and the fungal and microbial life associated with them as your primary food source?

Well, you likely wouldn't be...However, what about the way that the fishes, when introduced at the appropriate "phase" in the tank's life cycle- adapt to the tank? Wouldn't the fishes take advantage of these materials as a supplement to the prepared foods that you're feeding them? Doesn't this impact the fishes' genetic "programming" in some fashion? Can it activate some health benefits, behaviors, etc?

I believe that it can. And I believe that this type of more natural feeding ca profoundly and positively impact our fishes' health.

I’m no genius, trust me. I don’t have half the skills many of you do but I have succeeded with many delicate “hard-to-feed” fishes over my hobby “career.” 


Because I'm really patient.

Success with this approach is simply a result of deploying "radical patience."  The practice of just moving really slowly and carefully when adding fishes to new tanks. 

It's a really simple concept.

The hard part is waiting longer to add fishes.

Wait a minimum of three weeks—and even up to a month or two if you can stand it, and you will have a surprisingly large population of micro and macro fauna upon which your fishes can forage between feedings.

Having a “pre-stocked” system helps reduce a considerable amount of stress for new inhabitants, particularly for wild fishes, or fishes that have reputations as “delicate” feeders.

And think about it. This is really a natural analog of sorts. Fishes that live in inundated forest floors (yeah, the igapo again!) return to these areas to "follow the food" once they flood.

It just takes a few weeks, really. You’ll see fungal growth. You'll see some breakdown of the botanicals brought on by bacterial action or the feeding habits of small crustaceans and fungi. If you "pre-stock", you might even see the emergence of a significant  population of copepods, amphipods, and other creatures crawling about, free from fishy predators, foraging on algae and detritus, and happily reproducing in your tank.

We kind of know this already, though- right?

This is really analogous to the tried-and-true practice of cultivating some turf algae on rocks either in or from outside your tank before adding herbivorous, grazing fishes, to give them some "grazing material." 

Radical patience yields impressive results.

It’s not always easy to try something a little out of the ordinary, or a bit against the grain of popular practice, but I commend you for even thinking about the idea. At the very least, it may give you pause to how you stock your tank in the future, like  "Herbivores first, micro predators last", or whatever thought you subscribe to. 

Allow your system to mature and develop at least some populations of fauna for these fishes to supplement their diets with. You’ll develop a whole new appreciation for how an aquarium evolves when you take this long, but very cool road.

Stay patient. Stay observant. Stay creative. Stay studious. Stay resourceful...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Letting go...

So, you have this idea for an aquarium.

You kind of see it in your head...you've assembled the materials, got it sort of together.

You add water.

Then, you walk in the room one day, look at it and- you just HATE it.

Like, you're done with it.  Like, no re-hab on the design. No "tweaking" of the wood or whatever...You're just over the fucking thing. Ever felt that?

What do you do? 

Well, I had this idea for a nano tank a while back. It seemed good in my head...I had it up for a nanosecond.

Even memorialized it with some Instagram Stories posts. Doing that is almost always the sort of thing that forces me to move on something...I mean, if you lay down a public "marker", you've got to go, right?

I thought that the tank would be a sort of "blank canvas" for an idea I had...I liked the idea, in principle.

But I didn't see a way forward with this one. I even took the extraordinary step of removing one element of the tank (the wood) altogether, in the hope of perhaps pivoting and just doing my "leaf only scape V3.0"- but I wasn't feeling it.


A stillborn idea. A tank not capable of evolving to anything that interested me at this time.

So...I let it go.

Yeah, made away with it. Shut it down. Terminated it...

Whatever you want to call it.

That's really a kind of extraordinary step for me. I mean, I'm sort of the eternal optimist. I try to make almost everything work if I can...

I mean, some of my favorite tanks evolved out of this mindset of sticking with something...We'll come back to that in bit.

Not this time, however.

I killed it.

Now, in the hours after the aborted aquarium move, I was actually able to gain some clarity about why I did it.

What made me do it? 

I almost always do a sort of "post mortem" analysis when I abort on an idea, and this time was no different. It was pretty obvious to me...the "writing was on the wall" with this one!

I think it centered around two things that I simply can't handle in aquariums anymore.

Don't laugh:

1) I absolutely can't stand aquariums which don't have some sort of background- be it opaque window tint, photo paper, or paint. This tank had no background. You could see the window behind it, and the trees outside on the street, and...yeah. 

2) I disdain seeing filters or other equipment in my aquariums. Like, I hate it more than you can ever even imagine. With really few exceptions,  I simply hate seeing filters and stuff. It's only in recent years that I've been able to tolerate seeing filter returns in my all-in-one tanks...and just barely. Now, this nano had a little hang-on-the-back outside power filter...Which I not only saw from the top, but from behind...because-you got it- I didn't have a goddam background on the tank, yes.

I mean, am I that much of a primadonna that I can't handle that? I mean, maybe, but I like to think of it as a situation where I have simply developed an aesthetic sense that just can't tolerate some stuff anymore. I have good ideas, and then I get to equipment...and it sort of "stifles" them a bit.

This is weird.

Okay, yeah, maybe I am prima donna.

What could I have done to salvage this tank? Add a background?

Use a canister filter and glassware, you say?  

Oh, sure. That's easy, right? I mean, all you see in the tank are these elegant curves of "lily pipes" and intakes...Maybe a surface skimmer...You just take 'em out and bleach 'em every once in a while and they stay nice and clean, and..

Okay, yeah. Great. On paper, anyways.

IMHO, glassware isn't the "organic art" that everyone seems to place on some lofty pedestal in the hobby. It reminds me of high school chemistry lab (which I think I got a C minus in, so some residual trauma there, no doubt). You think it's beautiful...I think it's simply dreadful.

It's another piece of equipment, which you see on the outside of the tank, too, with its "umbilical" of return lines shooting up along the sides. Now sure, I know these were developed to make an obvious, visible necessity (filter returns) more elegant and beautiful...However, to me, they're just that- obvious, visible, distracting...and ugly.

Hell, I've even made crazy efforts to hide the canister filters beneath my tanks before, when I couldn't hide them within the tank. It's like, I had to do something! 

I know, I'm being waaaaay too stupid about this. 

Because, really, with a lot of my reef aquarium work, and for that matter, some of my fave botanical-style tanks, you can see some of this stuff. When you see my next reef tank, you might see couple of submersible pumps in the tank , low and deep behind the rock work.


For some reason, it doesn't completely fry my brain in every single situation. I suppose it's a hypocritical thing, but man, sometimes it freaks me out and sometimes I can give it a pass. 

Weird, huh?

Like, why do some tanks get a pass, and others just freak me out with this stuff.

I think, maybe, it's about the "concept"of the tank.  Or the context. Like, some of my fave ever tanks, like my leaf-litter-only tanks, typically will have some equipment evident, because they are essentially a "zero-releaf" aquascape, with nothing that you can hide this stuff behind, like wood or rocks, or whatever. It's as "honest" as it gets. If you want to filter and heat the tank, you only have few options.

It never bothered me all that much in those types of tanks.

Yet, in other tanks? Just fugettaboutit!

Yeah, it MUST be about the concept of the tank. Not only will I forgive the visible equipment, sometimes I'll forgive myself the entire poor execution, too. Because, when I look back at some of the stuff I've done, that was definitely the mindset. Like, I was just happy to sort of pull it off, despite how crappy it looked, as this little gem from 2004 graphically illustrates:


Now that I look back on it, there were actually tons of times when I just let a tank evolve, unmolested and unhurried, because something spoke to me...no matter how weird or seemingly dumb the concept may have initially appeared. There was something about it that I believed in...

And occasionally, I'll try something, tear it down, and just regret it. Like, I'll realize, too late, that there was something I liked about the idea, and that I should have kept at it; let it do it's thing.

Like, what IF I kept it in play for little longer?

I mean, could it have evolved into something cool?


I recall a particular experiment I did with Spider Wood, which I let go very early in the game. The arrangement was almost a "reef like" concept...It didn't look right at the time, so I killed it way too early.

Like, a few tweaks to the wood stack, a buildup of substrate in the back of it, a buildup of some leaves and maybe some plants in the back, and it could have been a respectable recreation of the banks of some of the forest floor streams that I've seen in South America.

Yeah, I'd love to try that one again.

Then there were others which I had great faith in right from the start. Even though they looked a bit weird initially, I knew that they'd evolve into something special if I let them be.

Some just hit  the right note, despite a possibly shaky start. Just knew that the idea was so special, that given the space and time, they'd eventually hit the right notes...And they did.

And, then, there were those ideas which, despite their unconventional appearance, were iconic to me, because they represented the culmination of although experiment; a transformation from research to idea to reality. Stuff which created a real transformation in the way I look at aquariums. The "Urban Igapo" style aquairums that many of us execute now, arose from just such an idea.

Sometimes, you just know it. You just feel that letting go of your preconceptions, doubts, and fears, rather than letting go of the tank-is just the right move.

Regardless of the idea, or the appearance of your tank, if there is any way to salvage what you feel is a great idea- even if it means just waiting it out for awhile-  do it. 


You just never know if that one "not so good"idea will turn out to be the one that changes everything for you, and inspires others in the process. Your "fail" might be the unlock- the key- for someone else who was about give up, and then suddenly saw something in your work, and created a tank based on your "failed" concept- executed on an idea-which truly touched others in ways you might not have even thought of.

So, yeah- let go...in the right way.

Stay bold. Stay patient. Stay creative. Stay optimistic. Stay enthusiastic. Stay persistent...

And Stay Wet.


Scott Fellman
Tannin Aquatics 

Evolving techniques

It's kind of fun to make little "tweaks" or adjustments to our aquarium methodology or approaches to how we do certain things. This is what pushes the state of the art in aquaristics further down the road. Now, not every one of these adjustments is a quantum leap forward, at least, not initially. Many are simply subtle iterations of things we've played with before.

An example?

One of our fave approaches, sort of derived out of our "Urban Igapo" work, has been to "dry set" the aquarium.  A sort of technique I call the "transitional approach." 

Basically, all you're doing is adding the prepared botanicals and leaves to your aquarium before it's filled, and spraying them down with water and our sprayable Purple Non-Sulphur bacterial inoculant, "Nurture" to kick-start the biological processes. Let it sit. Spray it down daily.

Then fill it.

Unlike in our "Urban Igapo" approach, you're not trying to grow terrestrial grasses or plants during the "dry phase." You're simply creating and managing  what will ultimately be the submerged habitat in your aquarium for a while before filling it.

I've done this a number of times and had great results.

Stupidly simple. Yet, profoundly different.


Because, rather than our "traditional" approach of adding the botanicals and leaves to the aquarium after it's already filled, you're sort of replicating what happens in Nature in the wild when forest floors and other terrestrial environments are inundated by overflowing streams and rivers.

The thing I like about this approach (besides how it replicates what happens in the wild) is that it gives you the ability to really saturate and soften  the botanicals and leaves, and to begin the process of decomposition and bacterial colonization before you add the water. 

When do you fill the aquarium?

You can wait a few days, a week or two, or as long s you'd like, really. The idea is to get the materials physically placed, and to begin the process of colonization and "softening" by fungi and bacterial biofilms- known as "conditioning" by ecologists who study these habitats. 

And of course, fishes and invertebrates which live amongst and feed directly upon the fungi and decomposing leaves and botanicals will contribute to the breakdown of these materials as well! Aquatic fungi can break down the leaf matrix and make the energy available to feeding animals in these habitats. And look at this little gem I found in my research:

"There is evidence that detritivores selectively feed on conditioned leaves, i.e. those previously colonized by fungi (Suberkropp, 1992; Graca, 1993). Fungi can alter the food quality and palatability of leaf detritus, aecting shredder growth rates. Animals that feed on a diet rich in fungi have higher growth rates and fecundity than those fed on poorly colonized leaves. Some shredders prefer to feed on leaves that are colonized by fungi, whereas others consume fungal mycelium selectively..."

"Conditioned" leaves, in this context, are those which have been previously colonized by fungi! They make the energy within the leaves and botanicals more available to higher organisms like fishes and invertebrates! 

We've long maintained that the appearance of biofilms and fungi on your botanicals and wood are to be celebrated- not feared. They represent a burgeoning emergence of life -albeit in one of its lowest and most unpleasant-looking forms- and that's a really big deal. 

"Oh shit, he's going to talk about biofilms AGAIN!"

Well, just for a second.

Biofilms, as we probably all know by now, form when bacteria adhere to surfaces in some form of watery environment and begin to excrete a slimy, gluelike substance, consisting of sugars and other substances, that can stick to all kinds of materials, such as- well- in our case, botanicals. It starts with a few bacteria, taking advantage of the abundant and comfy surface area that leaves, seed pods, and even driftwood offer.

The "early adapters" put out the "welcome mat" for other bacteria by providing more diverse adhesion sites, such as a matrix of sugars that holds the biofilm together. Since some bacteria species are incapable of attaching to a surface on their own, they often anchor themselves to the matrix or directly to their friends who arrived at the party first.

It's a literal explosion of life. It's a gift from Nature. And we can all receive it and benefit from it! 

Another advantage of this approach? The traditional "cycling" time of a new tank seems to go much faster. Almost undetectable, in many of my experiments. I can only hypothesize and assume that it's likely a result of all of the bacterial growth in the "terrestrial" phase, and the concurrent  "conditioning" of the botanical materials.  

Tannin's creative Director, Johnny Ciotti, calls this period of time when the biofilms emerge, and your tank starts coming alive "The Bloom"- a most appropriate term, and one that conjures up a beautiful image of Nature unfolding in our aquariums- your miniature aquatic ecosystem blossoming before your very eyes!

The real positive takeaway here: Biofilms are really a sign that things are working right in your aquarium! A visual indicator that natural processes are at work, helping forge your tank's ecosystem.

So, what about the botanicals?

The idea of utilizing botanicals in the aquarium can be whatever you want, sure. However, if you ask me (and you likely didn't)- the idea of utilizing these materials in our tanks has always been to create unique environmental conditions and foster a biome of organisms which work together to form a closed microcosm. That is incredible to me.

And the idea of "dry setting" your botanical materials and sort of "conditioning" them before adding the water, this "transitional approach", while not exactly some "revolutionary" thing, IS an evolutionary step in the development of botanical-style aquarium keeping.

The "transitional approach" is definitely a bit different than what we've done in the past, and may create a more stable, more biologically diverse aquarium, because you're already fostering a biome of organisms which will make the transition to the  aquatic habitat and "do their thing" that much more quickly.

This IS unique.

We're talking about actually allowing some of the decomposition to start before water is ever added to our tanks. It's a functional approach, requiring understanding, research, and patience to execute. There's really nothing difficult about it.

And the aesthetics? They're going to be different than what you're used to, no doubt. They will follow as a result of the process, and will resemble, on a surprisingly realistic level, what you see in Nature.

But the primary reason is NOT for aesthetics... 


The interactions and interdependencies between terrestrial and aquatic habitats are manifold, beneficial, and quite compelling to us as hobbyists. To be able to study this dynamic first hand, and to approach it somewhat methodically, is a significant change in our technique.

And yeah, it's almost absurdly easy to do.

The hard part is that it requires a bit more patience; not everyone will see the advantages, or value, and the trade-off between waiting to fill your tank and filling it immediately. It may not be one that some are willing to make.

If you do, however, you will get to see, firsthand, the fascinating dynamic between the aquatic and the terrestrial environment in a most intimate way.

It could change your thinking about how we set up aquariums. 

It could.

At the most superficial level, it's an acknowledgement that, after many decades, we as hobbyists are acknowledging and embracing this terrestrial-aquatic dynamic. It's a really unique approach, because it definitely goes against the typical "aquatic only" approach that we are used to.



When you consider that many aquatic habitats start out as terrestrial ones, and accumulate botanical materials and provide colonization points for various life forms, and facilitate biological processes like nutrient export and production of natural food resources, the benefits are pretty obvious. Again, the "different aesthetics" simply come along as "part of the package"- both in Nature and in the aquarium.

Replicating this process and managing it in the aquarium also provides us as hobbyists highly unique insights into the function of these habitats. 

From a hobby perspective, evolving and managing a closed ecosystem is really something that we should take to easily.

Setting up an aquarium in this fashion also provides us with the opportunity to literally "operate" our botanical-style aquariums; that is, to manage their evolution over time through deliberate steps and practices is not entirely unknown to us as aquarium hobbyists.

It's not at all unlike what we do with planted aquarium or reef aquarium. In fact, the closest analog to this approach is the so-called "dry start" approach to planted aquariums, except we're trying to grow bacteria and other organisms instead of plants.

Yes, it's an evolution.

Simply, a step forward out of the artificially-induced restraints of "this is how it's always been done"- even in our own "methodology"- yet another exploration into what the natural environment is REALLY like, how it evolves, and how it works- and understanding, embracing and appreciating its aesthetics, functionality, and richness.  

Earth-shattering? Not likely.

Educational? For sure.

Thought provoking and fun? Absolutely.

A simple, yet I think profound "tweak" to our approach.

Stay curious. Stay open-minded. Stay thoughtful. Stay observant. Stay creative.

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Cool Places.

As you know, we receive a lot of questions around here about all sorts of aquarium-related topics. Usually, my answer is directly to the individual who asked, in the form of an email or DM. Sometimes, however, the answer is such that it is best addressed in the form of a blog post! 

Recently, a hobbyist asked me what my opinion was of the botanical-style aquarium as a type of "aquascaping approach", and how it fits in the overall aquascaping "universe." Exactly what our "thing" is...

First, I start with my assertion that the botanical-style aquarium is NOT an aquascaping "style"- it's a methodology to create a more natural-functioning aquarium by utilizing botanical materials to "fuel" the process. The look is a "collateral benefit" of the methodology.

I admit, I've never really been much of an "aquascaper."

You know- those hobbyists who can take a few rocks and a piece or two of wood and turn them into some sort of amazing design. That takes amazing talent and vision. And I made peace with that decades ago! I greatly admire those true artists who can employ all sorts of technique, color-coordination, and ratio and such snd come up with some incredible stuff with seeming ease.

On the other hand, I look at a lot of aquascaping work, admire the effort and talent  and such, and then get this feeling in my gut that I can't always explain. Well, I can, but it's not always...nice. Like, I look at many "modern scapes" and just kind of...yawn.

Ouch, I'm sounding like a proper asshole, I know.

But seriously, it's not that I think their work is shitty or something...I just find the "styles" of many of the beautiful tanks out there which the world goes crazy over to be just a bit..boring. Or, should I say- not my taste. Yeah, that's better.

It's weird, I do like certain planted tanks that just blow me away. Our friend, George Farmer, does amazing planted 'scapes which I would happily have in my own home if I had the talent. I love the work of our own Johnny Ciotti- a guy who was trained as a classic "Nature Aquarium Style" 'scaper, yet, a true artist who can take botanical elements and create stunning botanical-style aquariums with ease. Jeff Sense of Aquarium Design Group is another person who can work with just about any "media" you give him- rocks, wood, plants- and crank out something that is unmistakingly original, dynamic, and gorgeous.


I'll never be as talented as those guys. And I'm perfectly okay with that. I'm comfortable in my own skin. And it's largely because, a long time ago, I found what I truly love, and work with that. I think we should all have that degree of comfort with what we love. Sadly, many hobbyists don't- and feel that-in order to be considered "talented" or whatever- that they have to embrace a certain style or technique.

That's absurd.

I often think about the so-called "diorama style" tanks that pop up in contests, and are all over Instagram or whatever. They require enormous talent to execute, but they're far more "art" than they are "natural aquariums", I suppose. And I guess that's what gets me- these weird fantasy scapes have live plants and glued-together rock and wood and stuff, but they are anything but "natural", IMHO.

I guess what gets me is that the aquascaping world lauds these scapes as "the shit"- and sure, they are fantastic- amazing work. When they're called "natural", that sends shivers down my spine...I mean, doesn't Nature offer scenes that are equally as complex, interesting, and challenging to pull off? And, with the added bonus that you can replicate the function of these habitats, I can't see why you don't see more representations of flooded forests, vernal pools, Pantanal meadows, etc. in the major aquascaping contests.

I imagine how amazing a tank one of those diorama-style 'scapers could pull off if he/she tried to replicate an actual aquatic habitat as found in Nature. With there talent and ability to bring a vision to life....wow! I mean, sure, such a tank won't have a beach scene, winding road into a forest, or a mountain range, or any of that other cliche stuff- but it will have all of the amazing vibrancy and intricate structure of natural aquatic habitats. The possibilities are endless.


I've postulated about why we don't see more of these things in contests..

However,  the benefits of entering tanks like this would be many, including calling attention to the wonders of the natural world, and the precious wild habitats which are often threatened by human activities.

I think that a good part of the reason is that these natural habitats aren't "tight" from a design standpoint. They don't -on the surface, at least-seem to require any "discipline" in order to replicate. You have to cede a certain amount of your work to Nature. I think that freaks out a lot of artistic aquascapers.

Nature, and Her many ecological niches and features, provides an endless array of habitats to recreate in the home aquarium. And my "POV" has always been to look at these niches, figure out how and why they formed, and why they look the way that they do. By researching the processes which helped create the habitat, I'm challenged to create an aquarium which attempts to replicate both the form and the function of it.

Some of these habitats are not what you'd expect to see in an aquairum. They look- and function- fundamentally different from what we've worked with before.

Some of the aesthetics of these wild habitats freaks people out. They look so...random...so...undisciplined, if we were to ascribe artistic terms to them. It's a world where we set up the system to allow Nature to do the "finishing" work. It require s a certain trust in natural processes, and the ability to let go. The ability to realize that what we see is a "finished product" is only the very beginning.

"The Delta at the intersection between science and art.” 

That's where I play. 

I like it here. A lot of you do, too.

This "not quite a biotope aquarium" and "not quite an artistic aquascape" thing is the perfect "sweet spot" for my interest, attention, and skills. And I think it's the place where I can be most useful to the hobby. Biotope-inspired, I suppose. A more forgiving, easygoing "style" which places function over aesthetics, yet somehow always leads to something that I find aesthetically pleasing.


It's a strange, yet wonderful place, where I've made the many "mental shifts" that allow me to enjoy the beauty and elegance of stuff like decomposing leaves, sediment, biofilms, fungal growths, random aggregations of leaves, etc. A place where much of the attraction is because the aquariums I create are intended to let Nature do some of the work. 

If I were forced (and yeah, "forced" is the right word, because there are no defining "rules" here...no way) to offer some defining characteristics of the  "botanical-style" aquarium, I'd say that a certain "randomness", actually, is it.

I mean, we're all about replicating what happens in Nature, NOT about perfectly proportioned placements and such. Now, I must admit, some of the world-class aquascapers that have worked with our botanicals have applied these concepts to these types of aquariums and have produced stunning results.

However, I think the "raw" botanical aquarium "essence" is about a certain degree of randomness.

And then there are details which nature can do best.



I believe that an aquarium that attempts to replicate a scene like the ones we're talking about starts with what looks like really artificial placement of wood, anchored by numerous details which soften, define, and fill in the scape. A sort of analog to the theater/motion picture concept  of "mise en scene", where pieces literally set the stage and help tell a story by providing context.

Yes, unlike a scape which depends upon growth of plants to fill it in and "evolve" it, the botanical-style blackwater/brackish aquarium is largely hardscape materials, which requires the adept placement of said materials to help fill in the scene. And of course, part of the "evolution" is the softening, redistribution, and break down of botanical materials over time...just like what happens in nature.

I suppose this little rant could be viewed as a "defense" our "style", which on occasion has been criticized as "sloppy", "lazy", "undisciplined", etc...😆

Perhaps it is to some. However, I think it serves to re-examine what I feel is one of the foundational philosophies of the botanical-style aquarium "aesthetic."

I must confess, it's an aesthetic which certainly doesn't appeal to everyone. In fact, many in the mainstream aquascaping world tended to levy all sorts of "constructive criticisms" and "Yeah, but..." comments about our practices and ideas for a while...Less these days, BTW!

And that is part of the attraction of this the of aquarium for me. Rather than conform thoroughly to some sort of "rules" based on design, layout, and technique, this type of aquarium tends to ask for very basic initial design, and lets Mother Nature handle a lot of the emerging details over time.

I think that there is a certain hunger for something different in the hobby right now.  I feel that we've dedicated most of this century to figuring out ways to push back against Nature's processes. We've spent a tremendous amount of time looking for ways to remove things that we don't feel belong in our tanks: Algae, biofilms, decomposition, etc. Stuff that we, as a hobby, feel to be unwelcome, unattractive, and even "detrimental."

And quite honestly, I think we see these things as undesirable or "unsafe" because they are artifacts of outdated thinking...holdovers from a time when we felt that our technology gave us the edge to accomplish what Nature couldn't. 

And of course, the reality is that the technology can accomplish some of these things, like nutrient export, heat control, circulation, etc.-but what really powers the miniature ecosystems which our aquariums actually are- is the microbiome: Fungal growths, bacterial biofilms, the process of decomposition, etc. Stuff which looks distasteful to many, yet stuff that is fundamental to the function-and yeah, the look- of our tanks. 

It's not just a look. Not just an aesthetic. Not just a mindset...

It's a way to incorporate natural materials to achieve new and progressive results with the fishes and plants we've come to love so much.

And, It's still early days.

A ground floor opportunity for every aquarist who gives this stuff a shot to make a meaningful- and beautiful contribution to the evolving state of the art of the botanical-style aquarium., and to share what Nature really looks like with people all over the world.

I'm fascinated by the "mental adjustments" that we need to make to accept the aesthetic and the processes of natural decay, fungal growth, the appearance of biofilms, and how these affect what's occurring in the aquarium. It's all a complex synergy of life and aesthetic.

And we have to accept Nature's input here.

Nature dictates the speed by which this decomposition process occurs. We set the stage for it- but  Nature is in full control. As an aquarist with a botanical-style aquarium, it's our "job" to observe and know when- or if- to intervene by adding or removing botanicals as they break down.

The great Takashi Amano's whole idea in a nutshell was to replicate Nature to a certain extent by accepting it and laying a conceptual groundwork for it to unfold. (Just look at all of the pics of grassy fields and moss-covered fenceposts in Amano's books. He got it. He felt something.) Now, granted, his general aesthetic involved plants and what seems to be a natural-looking aquascape, although executed in an intentionally artistic way.

There is nothing wrong with this. Some of the world's most beautiful aquariums were/are created this way. 

However, what I noticed over time in the freshwater world was an almost obsessive, rigid adherence to certain parts of Amano's formula and aesthetic; specifically, ratios, placement of hardscape and plants, and a certain type of aesthetic formula that one had to replicate in order to gain legitimacy or "acceptance" from the community. 

I really don't think it was Amano's intent.

"Wabi-sabi", the Japanese philosophy which embraces the ephemeral nature of the existence of things, was/is a key concept in Amano's approach, and it still is.

I think it's fallen into a bit of "disuse", though, in the "Nature Aquarium" movement, as aquarists aspired to replicate the style proffered in his works, perhaps trying to by-pass what seemed to be a less exciting -or less immediately rewarding- part of his approach.

I think that this is why we have some many  "diorama-style" tanks in competitions, with "details" like twigs and roots glued to wood...and I also think it's why we see more and more serious aquascapers taking another look at a more realistic type of aquarium utilizing botanicals. Aquariums which embrace decay, detritus, biofilms, and a less "ratio-centric", more "random" natural look.

I think many aquascapers are simply tired of overly-stylized and are leaning back into a truly more natural look. And maybe...perhaps- they're starting to come around to the idea of "functional aesthetics', too!

 A less rigidly aesthetically-controlled, less "high-concept" approach to setting the stage for...Nature- to do what she's done for eons without doing as much to "help it along." Rather, the mindset here is to allow nature to take it's course, and to embrace the breakdown of materials, the biofilms, the decay...and rejoice in the ever-changing aesthetic and functional aspects of a natural aquatic system- "warts and all" -and how they can positively affect our fishes.

Wabi-Sabi? Yeah, I think so. I think we embody the concept beautifully.

The initial skepticism and resistance to the idea of an aquarium filled with biofilms, decomposition, and tinted water has given way to enormous creativity and discovery. Our community has (rather easily, I might add!) accepted the idea that Nature will follow a certain "path"- parts of which are aesthetically different than anything we've allowed to occur in our tanks before- and rather than attempting to mitigate, edit, or thwart it, we're celebrating it!

"Functional aesthetics."

I think this is where Tannin Aquatics falls, if you had to nail us down into one specific "stylistic/philosphical approach" to aquariums.

The "space between", so to speak. Sort of straddling multiple approaches, with Nature as the ultimate "critic."

This can take us to some really cool places.

Let's go there.

Stay creative. Stay excited. Stay bold. Stay thoughtful...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

What our fishes eat...The wonder of food webs.

Yes, I admit that we talk about some rather obscure topics around here. Yet, many of these topics are actually pretty well known, and even well-understood by science. We just haven't consciously applied them to our aquarium work...yet.

One of the topics that we talk about a lot are food webs. To me, these are fascinating, fundamental constructs which can truly have important influence on our aquariums.

So, what exactly is a food web?


A food web is defined by aquatic ecologists as a series of "trophic connections" (ie; feeding and nutritional resources in a given habitat) among various species in an aquatic community. 

All food chains and webs have at least two or three of these trophic levels. Generally, there are a maximum of four trophic levels. Many consumers feed at more than one trophic level.

So, a trophic level in our case would go something like this: Leaf litter, bacteria/fungal growth, crustaceans...

In the wild aquatic habitats we love so much, food webs are vital to the organisms which live in them. They are an absolute model for ecological interdependencies and processes which encompass the relationship between the terrestrial and aquatic environments.

In many of the blackwater aquatic habitats that we're so obsessed with around here, like the Rio Negro, for example, studies by ecologists have determined that the main sources of autotrophic sources are the igapo, along with aquatic vegetation and various types of algae. (For reference, autotrophs are defined as organisms that produce complex organic compounds using carbon from simple substances, such as CO2, and using energy from light (photosynthesis) or inorganic chemical reactions.)

Hmm. examples would be phytoplankton!

Now, I was under the impression that phytoplankton was rather scarce in blackwater habitats. However, this indicates to scientists is that phytoplankton in blackwater trophic food webs might be more important than originally thought! 

Now, lets get back to algae and macrophytes for a minute. Most of these life forms enter into food webs in the region in the form of...wait for it...detritus! Yup, both fine and course particular organic matter are a main source of these materials. I suppose this explains why heavy accumulations of detritus and algal growth in aquaria go hand in hand, right? Detritus is "fuel" for life forms of many kinds.

In Amazonian blackwater rivers, studies have determined that the aquatic insect abundance is rather low, with most species concentrated in leaf litter and wood debris, which are important habitats.  Yet, here's how a food web looks in some blackwater habitats : Studies of blackwater fish assemblages indicated that many fishes feed primarily on burrowing midge larvae (chironomids, aka "Bloodworms" ) which feed mainly with organic matter derived from terrestrial plants!

And of course, allochtonous inputs (food items from outside of the ecosystem), like fruits, seeds, insects, and plant parts, are important food sources to many fishes.  Many midwater characins consume fruits and seeds of terrestrial plants, as well as terrestrial insects.

Insects in general are really important to fishes in blackwater ecosystems. In fact, it's been concluded that the the first link in the food web during the flooding of forests is terrestrial arthropods, which provide a highly important primary food for many fishes.

These systems are so intimately tied to the surrounding terrestrial environment. Even the permanent rivers have a strong, very predictable "seasonality", which  provides fruits, seeds, and other terrestrial-originated food resources for the fishes which reside in them. It's long been known by ecologists that rivers with predictable annual floods have a higher richness of fish species tied to this elevated rate of food produced by the surrounding forests.



And of course, fungal growths and bacterial biofilms are also extremely valuable as food sources for life forms at many levels, including fishes. The growth of these organisms is powered by...decomposing leaf litter! 

Sounds familiar, huh?

So, how does a leaf break down? It's a multi-stage process which helps liberate its constituent compounds for use in the overall ecosystem. And one that is vital to the construction of a food web.

The first step in the process is known as leaching, in which nutrients and organic compounds, such as sugars, potassium, and amino acids dissolve into the water and move into the soil.The next phase is a form of fragmentation, in which various organisms, from termites (in the terrestrial forests) to aquatic insects and shrimps (in the flooded forests) physically break down the leaves into smaller pieces. 

As the leaves become more fragmented, they provide more and more surfaces for bacteria and fungi to attach and grow upon, and more feeding opportunities for fishes!

Okay, okay, this is all very cool and hopefully, a bit interesting- but what are the implications for our aquariums? How can we apply lessons from wild aquatic habitats vis a vis food production to our tanks? 

This is one of the most interesting aspects of a botanical-style aquarium: We have the opportunity to create an aquatic microcosm which provides not only unique aesthetics- it provides nutrient processing, and to some degree, a self-generating population of creatures with nutritional value for our fishes, on a more-or-less continuous basis.

Incorporating botanical materials in our aquariums for the purpose of creating the foundation for biological activity is the starting point. Leaves, seed pods, twigs and the like are not only "attachment points" for bacterial biofilms and fungal growths to colonize, they are physical location for the sequestration of the resulting detritus, which serves as a food source for many organisms, including our fishes.

Think about it this way: Every botanical, every leaf, every piece of wood, every substrate material that we utilize in our aquariums is a potential component of food production!

The initial setup of your botanical-style aquarium will rather easily accomplish the task of facilitating the growth of said biofilms and fungal growths. There isn't all that much we have to do as aquarists to facilitate this but to simply add these materials to our tanks, and allow the appearance of these organisms to happen. 


You could add pure cultures of organisms such as Paramecium, Daphnia, species of copepods (like Cyclops), etc. to help "jump start" the process, and to add that "next trophic level" to your burgeoning food web. 

In a perfect world, you'd allow the tank to "run in" for a few weeks, or even months if you could handle it, before adding your fishes- to really let these organisms establish themselves. And regardless of how you allow the "biome" of your tank to establish itself, don't go crazy "editing" the process by fanatically removing every trace of detritus or fragmented botanicals.

When you do that, you're removing vital "links" in the food chain, which also provide the basis for the microbiome of our aquariums, along with important nutrient processing.

So, to facilitate these aquarium food webs, we need to avoid going crazy with the siphon hose! Simple as that, really!

Yeah, the idea of embracing the production of natural food sources in our aquariums is elegant, remarkable, and really not all that surprising. They will virtually spontaneously arise in botanical-style aquariums almost as a matter of course, with us not having to do too much to facilitate it.

It's something that we as a hobby haven't really put a lot of energy in to over the years. I mean, we have spectacular prepared foods, and our understanding of our fishes' nutritional needs is better than ever.

Yet, there is something tantalizing to me about the idea of our fishes being able to supplement what we feed. In particular, fry of fishes being able to sustain themselves or supplement their diets with what is produced inside the habitat we've created in our tanks!


A true gift from Nature. 

I think that we as botanical-style aquarium enthusiasts really have to get it into our heads that we are creating more than just an aesthetic display. We need to focus on the fact that we are creating functional microcosms for our fishes, complete with physical, environmental, and nutritional aspects.

Food production- supplementary or otherwise- is something that not only is possible in our tanks; it's inevitable.

I firmly believe that the idea of embracing the construction (or nurturing) of a "food web" within our aquariums goes hand-in-hand with the concept of the botanical-style aquarium. With the abundance of leaves and other botanical materials to "fuel" the fungal and microbial growth readily available, and the attentive husbandry and intellectual curiosity of the typical "tinter", the practical execution of such a concept is not too difficult to create.

We are truly positioned well to explore and further develop the concept of a "food web" in our own systems, and the potential benefits are enticing! 

Work the web- in your own aquarium!

Stay curious. Stay observant. Stay creative. Stay diligent. Stay open-minded...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Transitional Habitats...A new aquarium hobby frontier?

We've spent a lot of time over the least several years talking about the idea of recreating specialized aquatic systems. We've talked a lot about transitional habitats- ecosystems which alternate between terrestrial and aquatic at various times of the year.  These are compelling ecosystems which push the very limits of conventional aquarium practice. 

As you know, we take a "function first" approach, in which the aesthetics become a "collateral benefit" of the function. Perhaps the best way to replicate these natural aquatic systems inner aquariums is to replicate the factors which facilitate their function. So, for example, let's look at our fave habitats, the flooded forests of Amazonia or the grasslands of The Pantanal.

To create a system that truly embraces this idea in both form and function, you'd start the system as a terrestrial habitat. In other words, rather than setting up an "aquarium" habitat right from the start, you'd be setting up what amounts to a terrarium. Soil/sand, terrestrial plants and grasses, leaves, seed pods, and "fallen trees/branches" on the "forest floor."


You'd run this system as a terrestrial display for some extended period of time- perhaps several weeks or even months, if you can handle it- and then you'd "flood" the terrestrial habitat, turning it into an aquatic one. Now, I'm not talking about one of our "Urban Igapo" nano-sized tanks here- I"m talking about a full-sized aquarium this time.  

This is different in both scale and dynamic. After the "inundation", it's likely that many of the plants and grasses will either go dormant or simply die, adding other nutrient load in the aquarium.

A microbiome of organisms which can live in the aquatic environment needs to arise to process the high level of nutrients in the aquarium. Some terrestrial organisms (perhaps you were keeping frogs?) need to be removed and re-housed.

The very process of creating and populating the system during this transitional phase from terrestrial to aquatic is a complex, fascinating, and not entirely well-understood one, at least in the aquarium hobby. In fact, it's essentially a virtually unknown one. We simply haven't created all that many systems which evolve from terrestrial to aquatic.

Sure, we've created terrariums, paludariums, etc. We've seen plenty of "seasonally flooded forest" aquairums in biotope aquarium contests...But this is different. Rather than capturing a "moment in time", recreating the aquatic environment after the inundation, we're talking about recreating the process of transformation from one habitat to another.

Literally, creating the aquatic environment from a terrestrial one.

Psychologically, it would be sort of  challenging!

I mean, in this instance, you've been essentially running a "garden" for several months, enjoying it and meeting the challenges which arise, only to embark several months later on a process which essentially destroys what you've created, forcing you to start anew with an entirely different environment, and contend with all of its associated challenges (the nitrogen cycle, nutrient control, etc.)

Modeling the process. 

Personally, I find this type of approach irresistible. Not only do you get to enjoy all sorts of different aspects of Nature- you get to learn some new stuff, acquire new skills, and make observations on processes that, although common in Nature, were previously unrecorded in the aquarium hobby. 


You'll draw on all of your aquarium-related skills to manage this transformation. You'll deal with a  completely different aesthetic- I mean, flooding an established, planted terrestrial habitat filled with soils and plants will create a turbid, no doubt chaotic-looking aquascape, at least initially. 


This is absolutely analogous to what we see in Nature, by the way.Seasonal transformations are hardly neat and tidy affairs. 

Yes, we place function over form. However, that doesn't mean that you can't make it pretty! One key to making this interesting from an aesthetic perspective is to create a hardscape of wood, rocks, seed pods, etc. during the terrestrial phase that will please you when it’s submerged.

You'll need to observe very carefully. You'll need to be tolerant of stuff like turbidity, biofilms, algae, decomposition- many of the "skills"we've developed as botanical-style aquarists.You need to accept that what you're seeing in front of you today will not be the way it will look in 4 months, or even 4 weeks.

You'll need incredible patience, along with flexibility and an "even keel.”

We have a lot of the "chops" we'll need for this approach already! They simply need to be applied and coupled with an eagerness to try something new, and to help pioneer and create the “methodology”, and with the understanding that things may not always go exactly like we expect they should.

For me, this would likely be a "one way trip", going from terrestrial to aquatic. Of course, much like we've done with our "Urban Igapo" approach, this could be a terrestrial==>aquatic==>terrestrial "round trip" if you want! That's the beauty of this. You could do a complete 365 day dynamic, matching the actual wet season/dry season cycles of the habitat you're modeling.


The beauty is that, even within our approach to "transformational biotope-inspired" functional ecosystems, you CAN take some "artistic liberties" and do YOU. I mean, at the end of the day, it's a hobby, not a PhD thesis project, right?

Yeah. Plenty of room for creativity, even when pushing the state of the art of the hobby! Plenty of ways to interpret what we see in these unique ecosystems.

Habitats which transition from terrestrial to aquatic require us to consider the entire relationship between land and water- something that we have paid scant little attention to in the aquarium hobby, IMHO. 

And this is unfortunate, because the relationships and interdependencies between aquatic habitats and their terrestrial surroundings are fundamental to our understanding of how they evolve and function.

There are so many other ecosystems which can be modeled with this approach! Floodplain lakes, streams, swamps, mud holes...I could go on and on and on. The inspiration for progressive aquariums is only limited to the many hundreds of thousands of examples which Nature Herself has created all over the planet.

We should look at nature for all of the little details it offers. We should question why things look the way they do, and postulate on what processes led to a habitat looking and functioning the way it does- and why/how fishes came to inhabit it and thrive within it.

With more and more attention being paid the overall environments from which our fishes come-not just the water, but the surrounding areas of the habitat, we as hobbyists will be able to call even more attention to the need to learn about and protect them when we create aquariums based on more specific habitats.

The old adage about "we protect what we love" is definitely true here!

And the transitional aquatic habitats are a terrific "entry point"into this exciting new area of aquarium hobby work.

Stay inspired. Stay creative. Stay observant. Stay resourceful. Stay diligent...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

Someplace like...home?

Like so many of you, I am utterly awed by the sheer variety of tropical fish species that we've managed to breed in our aquariums over the decades. This is a testimony to the skill set and dedication of talented hobbyists and commercial breeders worldwide. And with obvious implications for some wild populations of fishes whose habitats arena danger, the idea of breeding fishes is a timely one.

Of course, there are absolutely benefits to a well-managed wild fishery, too, including protection of resources, economic benefits to indigenous peoples, and the preservation of wild populations. Programs like Project Piaba in Brazil have shown the tangible benefits to the people, environment, and the fishes that may be had with a properly-managed program of sourcing wild-caught fishes.

And, when it comes to the way we keep our fishes in the hobby on an everyday basis, I find a very interesting dichotomy here...

Have you ever thought about the way we've "domesticated" the fishes that we keep in our aquariums? I mean, the way we have sort of categorically "made" fishes more accommodating of the environmental conditions that we would like to provide them with in our aquariums? For example,  we've proudly advertised that fishes like Discus don't require soft, acidic water to thrive and reproduce. In fact, a number of breeders spawn and rear them in harder, more alkaline conditions.

This is interesting and makes me think about this from multiple angles...good and bad.

As you know, I tend to spend a fair amount of time snooping around the scientific literature online, looking for tidbits of information that might fit nicely into our fascination and evolving technique with natural blackwater and brackish- aquariums.

It's a pretty fun, albeit geeky- pastime, really- and quite educational, too!

And one of the interesting things about sifting through much of the scientific stuff is that you can occasionally find bits and pieces of information which may not only confirm a "hunch" that you have had about something- these data can sometimes send you into an entirely new direction! (I know that it can, lol!)

As a lover of brackish-water habitats, I've spent a lot time over the years researching suitable fishes and other aquatic organisms from this environment for aquarium keeping. I've made a lot of interesting discoveries about brackish water habitats and the fishes which supposedly occur in them. 

Notice I use the term "supposedly..?"

Interestingly, many of the fishes that we in the hobby have assigned the "brackish" moniker to are actually seldom found in these types of habitats. Perhaps some small populations of some of these fishes might be from mildly brackish environments, but many of them are primarily found in pure freshwater.

Perhaps through a combination of misinformation, assumption, and successful practice by a few hobbyists over the years, we've sort of attached the "brackish water fish" narrative to them in general.

Now, sure, many fishes can adapt to brackish water conditions, but I'm more fascinated by the fishes which are actually found naturally in these environments. And it's always interesting when you can find out that a fish which you have previously dismissed as not having typically come from this environment actually does come from it naturally!

It's like a little discovery!

One of those happy "surprises" is our good friend, the "Endler's Livebearer", Poceilia wingei. Many of you love this fish and keep it extensively. 

This popular fish is widely kept under "typical livebearer conditions" in the aquarium ( higher pH and harder water).

However, there are a number of wild populations form their native Venezuela which inhabit mildly brackish water coastal lagoons and estuaries, for example, Laguna de los Patos, near Cumana, which has definite ocean influence, although it is far less salty than researchers thought it may have been in the past. And the wild populations residing there might very well be considered "endangered", or at least, limited.

Now, this kind of stuff is not "revolutionary" from a hobby standpoint, as it seems like we've known this for some time. And although the fish are very adaptable, we don't hear all that much about keeping them in what we'd call "brackish" conditions (like typically SG of 1.003-1.005, although I like to push it a bit higher, lol). It's just interesting to ponder and kind of get your head around.

And with all of the popularity of this fish, it seems to me like the brackish water habitat for this species has not been embraced much from a hobby standpoint.

And I suppose it makes sense- it's far easier to simply give fishes harder, alkaline water than to "mess with adding salt" to their tanks for a lot of hobbyists. In addition, wild populations of these fishes are scant, as is natural habitat data, so indeed confirming with any great certainty that they are even still occurring in these types of habitats is sketchy.

And often, so-called 'populations" of fishes in these specialized habitats might have been distributed as a result of actions by man, and are not even naturally occurring there- further confounding things!

In general, the question about adding salt to livebearer tanks has been debated for a long time, and there are many views on the subject. Obviously, the ultimate way to determine if you should or should not add salt to an Endler's or other livebearer tank would be to consider the natural habitats of the population you're working with.


Easier said than done, because  the vast majority of them are now commercially or hobbyist bred for generations- especially Endler's- and wild collection data is not always easy to obtain.

I think the debate will go on for a long time!

Yet, with the increasing popularity of brackish water aquariums, we're hoping to see more experiments along this line for many different species! I was recently very happy to secure some specimens of the miserably-named "Swamp Guppy", Micropoceilia picta, a fish which absolutely does come from brackish water. And I have no intention of ever "adapting" them to environmental conditions which are more "convenient" for us hobbyists!

Now, you know I've always been a fan of sort of "re-adapting" or "re-patriating" even captive-bred specimens of all sorts of fishes (like "blackwater-origin" characins, cichlids, etc.) to more "natural" conditions (well, "natural" from perhaps a few dozen generations back, anyhow). I am of the opinion that even "domesticated" fishes can benefit from providing them with conditions more reminiscent of those from the natural habitats from which they originated.

Although I am not a geneticist or biological ethicist, I never will buy into the thought that a few dozen captive generations will "erase" millions of years of evolutionary adaptation to specific habitats, and that re-adapting them to these conditions is somehow "detrimental" to them. Something just seems "off" to me about that thinking.

I just can't get behind that.

Now, even more compelling "proof" of that it's not so "cut-and-dry" is that many of the recommended "best practices" of breeding many so-called "adaptable" species are to do things like drop water temperatures, adjust lighting, or perform water exchanges with peat-influenced water, etc....stuff intended to mimic the conditions found in the natural habitats of the fishes...

I mean...WTF? Right? 

Like, only give the fishes their "natural" conditions when we want to breed them? Really? That mindset just seems a bit odd to me...

Of course, there are some fishes for which we don't really make any arguments against providing them with natural-type environmental conditions, such as African rift lake Cichlids.

I find this absolutely fascinating, from a "hobby-philosopher" standpoint!

And then, there are those fishes which we have, for various reasons (to minimize or prevent the occurrence of diseases) arbitrarily decided to manipulate their environment deliberately away from the natural characteristics under which they evolved for specific reasons. For example, adding salt to the water for fishes that are typically not known to come from brackish habitats.

Examples are annual Killifishes, such as Nothobranchius, which in many cases don't come from brackish environments naturally, yet we dutifully add salt to their water as standard practice. The adaptation to a "teaspoon of salt per gallon" or so environment is done for prophylactic reasons, rather than what's "convenient" for us- a rather unique case, indeed...and again, something that I find fascinating to look at objectively.

Is salt simply the easiest way to prevent parasitic diseases in these fishes, or are there other ways which don't require such dramatic environmental manipulations?

And then, of course, there are those unexpected populations of fishes, like various Danios and Gold Tetras, for example, which are found in mildly brackish conditions...Compelling, interesting...yet we can't conclude that all Gold Tetras will benefit from salt in their water, can we?

And, as we evolved to a more sustainable hobby, with greater emphasis on captive -bred or carefully-sourced wild fishes, and as more wild habitats are damaged or lost, will we also lose valuable data about the wild habitats of the fishes we love so much?  

Data which will simply make the "default" for many fishes to be "tap water?"

I hope not.

Is it possible, though, that we've been so good at "domesticating" our fishes to our easier-to-provide tap water conditions- and our fishes so adaptable to them- that the desire to "repatriate" them to the conditions under which they've evolved is really more of a "niche" thing for geeky hobbyists, as opposed to a "necessary for success" thing?

I mean, how many Discus are now kept and bred exclusively in hard, alkaline water- markedly different than the soft, acid blackwater environmental conditions under which they've evolved for eons? Am I just being a dreamer here, postulating without hard data that somehow the fishes are "missing something" when we keep and breed them in conditions vastly different than what the wild populations come from?

Do the same genetics which dictate the color patterns and fin morphology also somehow "cancel out" the fish's "programming" which allows them to be healthiest in their original native conditions?

How do we reconcile this concept?

In the end, there are a lot of variables in the equation, but I think that the Endler's discussion is just one visible example of fishes which could perhaps benefit from experimenting with "throwback" conditions. I'm by no means anything close to an expert on these fish, and my opinions are just that- opinions. Commercially, it may not be practical to do this, but for the hobbyist with time, resources, and  inclination, it would be interesting to see where it takes you.  

Like, would the same strain kept in both brackish and pure freshwater habitats display different traits or health characteristics?

Would there even be any marked differences between specimens of certain fishes kept under "natural" versus "domesticated" conditions? Would they show up immediately, or would it become evident only after several generations? And again, I think about brackish-water fishes and the difficulty of tracing your specimens to their natural source, which makes this all that much more challenging!

I look forward to many more such experiments- bringing natural conditions to "domesticated" fishes, and perhaps unlocking some more secrets...or perhaps simply acknowledging what we all know:

That there truly is "no place like home!"

Stay observant. Stay curious. Stay adventurous. Stay resourceful. Stay experimental. Stay relentless...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

It's about the microbiome...


As we've all started to figure out by now, our botanical-influenced aquariums are a lot more of a little slice of Nature that you're recreating in your home then they are just a "pet-holding container."

The botanical-style aquarium is a microcosm which depends upon botanical materials to impact the environment.

This microcosm consists of a myriad of life format all levels and all sizes, ranging from our fishes, to small crustaceans, worms, and countless microorganisms. These little guys, the bacteria and Paramecium and the like, comprise what is known as the "microbiome" of our aquariums.

A "microbiome", by definition, is defined as "...a community of microorganisms (such as bacteria, fungi, and viruses) that inhabit a particular environment." (according to Merriam-Webster)

Now, sure, every aquarium has a microbiome to a certain extent:

We have the beneficial bacteria which facilitate the nitrogen cycle, and play an indespensible role in the function of our little worlds. The botanical-style aquarium is no different; in fact, this is where I start wondering...It's the place where my basic high school and college elective-course biology falls away, and you get into more complex aspects of aquatic ecology in aquariums.

Yet, it's important to at least understand this concept as it can relate to aquariums. It's worth doing a bit of research and pondering. It'll educate you, challenge you, and make you a better overall aquarist. In this little blog, we can't possibly cover every aspect of this- but we can touch on a few broad points that are really fascinating and impactful.

So much of this proces-and our understanding starts with...botanicals. 

With botanicals breaking down in the aquarium as a result of the growth of fungi and microorganisms, I can't help but wonder if they perform, to some extent, a role in the management-or enhancement-of the nitrogen cycle.

Yeah, you understand the nitrogen cycle, right?

How do botanicals impact this process? Or, more specifically, the microorganisms that they serve?

In other words, does having a bunch of leaves and other botanical materials in the aquarium foster a larger population of these valuable organisms, capable of processing organics- thus creating a more stable, robust biological filtration capacity in the aquarium? 

I believe that they do.

With a matrix of materials present, do the bacteria (and their biofilms- as we've discussed a number of times here) have not only a "substrate" upon which to attach and colonize, but an "on board" food source which they can utilize as needed?

Facultative bacteria, adaptable organisms which can use either dissolved oxygen or oxygen obtained from food materials such as sulfate or nitrate ions, would also be capable of switching to fermentationor anaerobic respiration if oxygen is absent.


Well, that's likely another topic for another time. Let's focus on some of the other more "practical" aspects of this "biome" thing.

Like...food production for our fishes.

In the case of our fave aquatic habitats, like streams, ponds, and inundated forests, epiphytes, like biofilms and fungal mats are abundant, and many fishes will spend large amounts of time foraging the "biocover" on tree trunks, branches, leaves, and other botanical materials.

The biocover consists of stuff like algae, biofilms, and fungi. It provides sustenance for a large number of fishes all types.

And of course, what happens in Nature also happens the aquarium- if we allow it to, right? And it can function in much the same way?


I am of the opinion that a botanical-style 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. Detritus and the microorganisms within it can provide an excellent supplemental food source for our fishes!

Sustenence...from the microbiome.

It's well known that in many habitats, like inundated forests, etc., fishes will adjust their feeding strategies to utilize the available food sources at different times of the year, such as the "dry season", etc.

And it's also known that many fish fry feed actively on bacteria and fungi in these habitats...So I suggest once again that a botanical-style aquarium could be an excellent sort of "nursery" for many fish and shrimp species! 

Again, it's that idea about the "functional aesthetics" of the, botanical-style aquariums. The idea which acknowledges the fact that the botanicals we use not only look cool, but they provide an important function (supplemental food production) as well. As we repeat constantly, the "look" is a collateral benefit of the function.

This is a profoundly important idea.

Perhaps arcane to some- but certainly not insignificant.

And of course, we've talked before about this "botanical nursery" concept- creating an aquarium for fish fry that has a large quantity of decomposing botanicals and leaves to foster the production of these materials, which serve as supplemental food for your fish fry. I have done this before myself and can attest to its viability. You fishes will have a constant supply of "natural" foods to supplement what you are feeding them in the early phases of their life.

Learn to make peace with your detritus! As always, look to the wild aquatic habitats of the world for an example of how this food source functions within the greater biome.

I'm fascinated by the "mental adjustments" that we need to make to accept the aesthetic and the processes of natural decay, fungal growth, the appearance of biofilms, and how these affect what's occurring in the aquarium. It's all a complex synergy of life and aesthetic.

And,  in order to make the mental shifts which make this all work, we we have to accept Nature's input here.

Understand that, when we create a botanical-filled aquarium, not only do we have the opportunity to create an aquarium which differs significantly from those in years past- we have a unique window into the natural world and the role of these materials in the wild.

One thing that's very unique about the botanical-style approach is that we tend to accept the idea of decomposing materials accumulating in our systems. We understand that they act, to a certain extent, as "fuel" for the micro and macrofauna which reside in the aquarium, and that they perform this function as long as they are present in the system.

A profound mental shift...

And it's all about the microbiome. today's simple idea with enormous impact!

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

And Stay Wet.


Scott Fellman

Tannin Aquatics