Perpetual darkness...

Okay, that was an admittedly "dark"-sounding title, but it's perfectly appropriate for today's topic...How to get- and keep- your water as tinted as possible. Or, at least, what materials would do the best job in terms of "color production."

We as a group are kind of obsessed with this.

And yeah, it's a good question!

Now, first off- let's all remember that the color of the water has absolutely NO relationship to its pH or carbonate hardness. It just doesn't. You can have water that looks super dark brown, yet has a pH of 8.5 or whatever. And conversely, it's just as possible to have crystal clear blue-white water that's soft, and has a pH of 4.5. We have to get beyond the social media-style "blackwater" definition, which seems to be, "If the water is tinted, it's a blackwater aquarium!"

Now, look, if you just want the nice color but could care less about the pH and hardness, that's fine. For the benefit of the hobby as a whole, please don't perpetuate the confusing narrative about blackwater aquariums by telling others that you have "blackwater." You have a "tinted" aquairum. 

And that's just fine.

So, yeah-I'm not going to launch into a long drawn out description today about how ecologists define "blackwater" and what specific chemical characteristics make it up- we've covered it enough over the can deep dive here or elsewhere to get that. 

Okay, micro-rant over. Let's get back to the topic.

Remember, this piece is not about how to make blackwater...It's a little more superficial than's about creating an aquarium with color and maintaining it. 

First off, one of the "keys" to getting your color that lovely brown is to select the right types and quantities of botanical materials to assist. Now, I'll be the very first to raise my hand and call BS on anyone who claims to have a perfect "recipe" for how many Catappa leaves per liter or whatever you must use to achieve a specific color. Sure, you could come up with some generic recommendations, but they're not always applicable to every tank or situation.

Yes...there are simply so many variables in the equation- many which we probably haven't even considered yet-that it would be simply guessing. Just like Nature, to some extent...

What I can do is recommend some materials which we have found over the years to generally impart the most reliable and significant color to water. In no particular order, I'll give you my thought on a few of my personal faves. There are a lot more, but these are some that consistently show up on my "fave" list. 


Yep, you heard me. One of the very best sources of tint-producing tannins in our aquariums is wood. I've told you many times, wood imparts tannins, lignin, and all sorts of other "stuff" from the exterior surfaces and all of those nooks and crannies that we love so much into the water. 

Ahh...the tannins.

Now, I don't know about you, but I'm always amused (it's not that hard, actually) by the frantic posts on aquarium forums from hobbyists that their water is turning brown after adding a piece of wood. I mean- what's the big deal?

Oh, yeah, not everyone likes it...I forgot that. 😂

The reality, though, as you probably have surmised, is that wood will continue to leach tannins to a certain extent pretty much for as long as it's submerged. As a "tinter", I see this as a great advantage in helping establish and maintain the blackwater look, and to impart humic substances that are known to have health benefits for fishes.

Some wood types, like Mangrove ( a wood we don't have at the moment), tend to release more tannins than others over long periods of time. Other types, like "Spider Wood", will release their tannins relatively quickly, in a big burst. Some, such as Manzanita wood, seem to be really "dirty", and release a lot of materials over long periods of time. All will recruit fungal growths and bacterial biofilms.

And  the biocover on the wood is a unique functional aesthetic, too, as we rant on and on about here!


I'm a huge fan of tree bark to impart not only color, but beneficial tannins into the water. Because of its composition and structure, bark tends to last a very long time when submerged, and tends to impart a lot of color to the water over the long term.

And to be quite honest, almost all of the bark products we've played with over the years seem to work equally as well. The real difference in bark is the "form factor" (appearance) and the color that they impart to the water over time. Some, such as Red Mangrove bark or Cutch bark, will impart a much deeper, reddish-brown tint to the water than say, an equal quantity of catappa bark. And our soon-to-be-released Ichnocarpus bark really packs in this reddish brown color! You're gonna love this stuff! 

Ounce for ounce, gram for gram, I've always felt that various types of bark always impart the most color to the water over almost any other materials.

"Skyfruit Pods" 

These are very interesting, woody pods, derived from the outer "valve" of the fruit of the Swietenia macrophylla tree, which hails from a wide range of tropical locales (although native to Brazil), and are just the sort of thing you'd find floating or submerged in a tropical jungle stream. Often called "Skyfruit" by locals in the regions in which they're found because they hang from the trees- a name we fell in love with!

These botanicals can leach a terrific amount of tannins, akin to a similar-sized piece of Mopani wood or other driftwood. They are known to be full of flavonoids, saponins, and other humic substances, which have known positive health effects on fishes. Like bark, it lasts a good long time and recruits some biofilms and fungal growths for good measure.

Live Oak Leaves/Magnolia Leaves 

Despite their humble North American origins, these leaf types impart more color, ounce per ounce, than just about any of our fave tropical leaves. And they both last very long time...Like, I've had specimens of live oak leaves stay intact for several months!

It's really important to think of leaves as not just a "coloring agent" for your water, but as a sort of biological support mechanism for your burgeoning ecosystem. They actively recruit fungi, bacterial biofilms, and other microorganisms which enrich the overall aquatic environment in your tank.




Alder cones  (Aalnus glutinosa and Alnus incana)  and Birch cones (Betula occidentalis), have  been widely utilized by aquarium hobbyists in Europe for some time. Betta and ornamental shrimp breeders are fond of the tannins released into the water by these cones, and their alleged anti fungal and antibacterial properties. There has also been much study by hobbyists about the pH reduction attributes of these cones, too.

A study done a few years back by a Swedish hobbyist using from one to six cones in a glass containing about 10 ounces of tap water, with a starting ph of around 8.12, was able to affect a drop to 6.74 with one cone after about two weeks, 4.79 with 2 cones after two weeks, and an amazing 3.84 with 6 cones after the same time period! The biggest part of the drop in pH occurred in the first 12 hours after immersion of the cones!

Now, I'm the last guy to tell you that a bunch of cones is the perfect way to lower pH, but this and other hobby-level studies seem to have effectively have demonstrated their ability to drive pH down in "malleable" (soft) water...

 Coconut-based products (Coco Curls, "Fundo Tropical", "Substrato Fino")

There's something about coconuts...The materials which are derived from the husks of coconuts seem to produce a significant amount of tannins and impart color to the water. Of course, "Substrate Fino" and "Fundo Tropical" are smaller, or finer-textured materials which work primarily as "substrate enhancers", and not strictly as "color-producing agents", because there is an initial "burst", which subsides over time. 

Now, one of the novel applications for these finer botanical materials to take advantage of their color producing ability is to place them in a fine mesh filter bag and allow water to flow around or through them, like filter media. Essentially, a more sustainable alternative to the old peat moss trick...

Oak Twigs

For an interesting look and some nice color, I'm a big fan of oak twigs. Oak has a nice bark which imparts a deep brownish/yellow color to the water and it's quite distinctive. There is a reason why our  "Twenty Twigs" packs are pretty popular, and it's not just because you get a bunch of cool sticks!

When mixed with leaves and/or other botanical materials, not only do you get an incredible "framework" for a cool ecosystem, you get an incredible aesthetic as well!

Now, this is an absolutely cursory list.. I could have easily listed 10 or more items. No doubt, some of you hardcore enthusiasts are screaming at your screens now: "WTF Fellman, you didn't include_______!"

And of course, that's the beauty of natural materials...There are numerous options!

Another note on the colors to expect from various botanical materials. As you might suspect, many of the lighter colored ones will impart a correspondingly lighter tint to the water. And, some leaves, such as Guava or Loquat, also impart a  more yellowish or golden color to the water, as opposed to the brownish color which Jackfruit and Catappa are known for. 

A lot of you ask about things that impact how long the water retains it's tint.

This kind stuff is a big deal for us- I get it! Many hobbyists who have perhaps added some catappa leaves, "blackwater extracts", or rooibos tea to their water contact me asking  stuff like why the water doesn't stay tinted for more than a few days. Now, I'm flattered to be a sort of "clearing house" for this stuff, but I must confess, I don't have all the answers.

So, "Why doesn't my water stay tinted, Scott?"

Well, I admit I don't know. Well, not for certain, anyways!

I do, however, have some information, observations, and a bunch of ideas about this- any of which might be literally shot to pieces by someone with the proper scientific background. However, I can toss some of these seemingly uncoordinated facts out there to give our community some stuff to "chew on" as I offer my ideas up.

Now, perhaps it starts with the way we "administer" the color-producing tannins. 

Like, I personally think that utilizing leaves, bark, and seed pods is perhaps the best way to do this. I'm sure that you're hardly surprised, right? Well, it's NOT just because I sell these material for a living...It's because they are releasing tannins, humic substances, and other compounds into the water "full time" during their presence in the aquarium as they break down. A sort of "on-board" producer of these materials, with their own "half life" (for want of a better term!).

And, they also perform an ecological role, providing locations for numerous life forms (like fungal growths) surface area upon which to colonize. They become part of the ecosystem itself. A few squirts of "blackwater extracts" won't do that, right?

The continuous release of tint-producing compounds from botanical materials keeps things more-or-less constant. And, if you're part of the "school" which leaves your botanicals in your aquarium to completely break down, you're certainly getting maximum value out of them! And if you are continuously adding/replacing them with new ones as they completely or partially break down, you're actively replenishing and adding additional "tint-producing" capabilities to your system, right?

There is another way to "keep the tint" going in your tanks, and it's pretty easy. Now, those of you who know me and read my rambling or listen to "The Tint" podcast regularly know that I absolutely hate shortcuts and "hacks" in the aquarium hobby. I preach a long, patient game and letting stuff happen in its own time...

Nonetheless, there ARE some that you can employ that don't make you a complete loser, IMHO.😆

When you prepare your water for water changes, it's typically done a few days to a week in advance, so why not use this time to your advantage and "pre-tint" the water by steeping some leaves in it? Not only will it keep the "aesthetics" of your water ( can you believe we're even talking about "the aesthetics of water?") consistent (i.e.; tinted), it will already have humic substances and tannins dissolved into it, helping you keep a more stable system.

Obviously, you'd still check your pH and other parameters, but the addition of leaves to your replacement water is a great little "hack" that you should take advantage of. (Shit, I just recommended a "hack" to you...)

It's also a really good way to get the "look" and some of the benefits of blackwater for your system from the outset, especially for those of you heathens that like the color of blackwater and despise all of the decomposing leaves and seed pods and stuff!

So, if you're just setting up a brand new aquarium, and have some water set aside for the tank, why not use the time while it's aging to "pre-tint" it a bit, so you can have a nice dark look from day one? It's also great if you're setting up a tank for an aquascaping contest or  other same-day club event that would make it advantageous to have a tinted tank immediately.

I must confess that yet another one of the more common questions we receive here from hobbyists is, "How can I get the tint in my tank more quickly?"- and this is definitely one way!

How many botanicals to use to accomplish this?

Well, that's the million dollar question.

Who knows?

It all gets back to the (IMHO) absurd "recommendations" that have been proffered by vendors over the years recommending using "x" number of leaves, for example, per gallon/liter of water. There are simply far, far too many variables- ranging from starting water chem to pH to alkalinity, and dozens of others- which can affect the "equation" and make specific numbers unreliable at best. 

We did, too, in the early days of Tannin. And it was kind of stupid really. There just is no hard-and-fast answer to this. Every situation is different. You need to kind of go with your instinct. Go slowly. Evaluate the appearance of your water, the behaviors of the fishes...the pH, hardness, TDS, nitrate, phosphate, or other parameters that you like to test for.

It's really a matter of experimentation.

I'm a much bigger fan of "tinting" the water based on the materials in the aquarium. Letting Nature have at it. The botanicals will release their "contents" at a pace dictated by their environment. And, when they're "in situ", you have a sort of "on board" continuous release of tannins and humic substances based upon the decomposition rate of the materials you're using, the water chemistry, etc.

Replacement of botanicals, or addition of new ones, as we've pointed out many times, is largely a subjective thing, and the timing, frequency, and extent to which materials are removed or replaced is dependent upon multiple factors, ranging from base water chemistry to temperature, to the types of aquatic life you keep in the tank (ie; xylophores like certain Plecos, or strongly grazing fishes, like Headstanders, will degrade botanicals more quickly than in a tank full of characins and such).

(The part where Scott bashes the shit out of the idea of using "blackwater extracts" and Rooibos tea. This could get nasty!)

If you haven't heard of it before, there is this stuff called Rooibos tea, which, in addition to bing kind of tasty, has been a favored "tint hack" of many hobbyists for years. Without getting into all of the boring details, Rooibos tea is derived from the Aspalathus linearis plant, also known as "Red Bush" in South Africa and other parts of the world. 

(Rooibos, Aspalathus linearis.  Image by R.Dahlgr- used under CC-BY S.A. 2.5)

It's been used by fish people for a long time as a sort of instant "blackwater extract", and has a lot going for it for this purpose, I suppose. Rooibos tea does not contain caffeine, and and has low levels of tannin compared to black or green tea. And, like catappa leaves and other botnaicals, it contains polyphenols, like flavones, flavanols, aspalathin, etc. 

Hobbyists will simply steep it in their aquariums and get the color that they want, and impart some of these substances into their tank water. I mean, it's an easy process. Of course, like any other thing you add to your aquarium, including leaves and botanicals, it's never a bad idea to know the impact of what you're adding. 

Like using botanicals, utilizing Rooibos tea bags in your aquarium requires some thinking, that's all. 

The things that I personally dislike about using tea or so-called "blackwater extracts" are that you are simply going for an effect, without getting to embrace the functional aesthetics imparted by adding leaves, seed pods, etc. to your aquarium as part of its physical structure and ecology, and that there is no real way to determine how much you need to add to achieve______.

Obviously, the same could be said of botanicals, but we're not utilizing botanicals simply to create brown water or to target specific pH parameters, etc. We're trying to create an ecology that is similar to what you'd see in such habitats in Nature.

Yet, with tea or commercial blackwater extracts, you sort of miss out on replicating a little "slice of Nature" in your aquarium. The building of an ecosystem.  Which is why we call this the botanical method. It's not a "style" of aquascaping! And of course, it's fine if your goal is just to color the water, but it's more of an aesthetically-focused aquarium at that point.

I also understand that some people, like fish breeders who need bare bottom tanks or whatever- like to condition water without all of the leaves and twigs and nuts we love. They want the humic substances and tannins, but really don't need/want the actual leaves and other materials in their tanks.

And, when it comes to tea and these commercial extracts, I don't think the stuff lasts all that long. I personally believe that the tint-producing tannins in "tea" are potentially taken up quickly by substrate materials, filter media, etc. And unless you're keeping tea bags in your tank on a continuous basis, you'll always experience some "color loss" after some period of time.

Yes it works to impart some color and tannins. Creating infusions or extracts is useful, if you understand their purpose and limitations. They have a place in the hobby for sure.

It's why we got into the game with our botanical-based "Shade" products. We're currently sold out and are working with our supplier on a reformulated version. Seems as though we need to make a "darker" mix!

On the other hand, if you're trying to replicate the look and function (and maybe some of the parameters) of THIS:

You won't achieve it by using THIS:

It's simply another shortcut.

Not good or bad. Just a way to get the end "effect" faster, and without the other collateral benefits we discussed.

And look, I understand that we are all looking for the occasional shortcuts and easier ways to do stuff. And I realize that none of what we proffer here at Tannin is an absolute science. It's likely more of an "art" at this point, with a little science behind it.

Think about it: There is no current way available to the hobby to test for "x" types or amounts of tannins (of which there are hundreds of types) in aquariums.  I mean, there are tannin test kits, but they're used for wine making and such...Perhaps there is some tangential application for our purposes, but I'm not really sure what practical information. we could extract from the results.

And, I have not found a study thus far which analyzed wild habitats (say, Amazonia) for tannin concentrations and specific types, so we have no real model to go on.

The best we can do is create a reasonable facsimile of Nature.

And, in Naturę, a lot of the tint in blackwater environments comes from dissolved fulvic and humic acids from...soils. Yeah, geology is the key, IMHO, to truly "realistic" blackwater habitats. This is why I've been very picky on sourcing the materials and figuring out recipes for our NatureBase sediment substrates. They are intended to support these types of systems.

Understanding substrates and their role in both the physical environment and the ecology of our aquariums is still a wildly under-appreciated concept in the aquarium hobby, IMHO. We'll keep coming back to this in the future, I'm certain.

And keeping the water tinted is something that many botanical method aquarists are interested in. This wonderful "collateral benefit" of our approach is something that's easy to get addicted to!

Now, all of these ideas are okay to impart some color to your water. Some do more, as we've discussed ad nauseam. And none of them will work to full advantage if your aquarium is removing them as fast as you're imparting them into the water. So, go easy on chemical filtration media like carbon. I didn't say NOT to use them...Just don't use a ton of them! Use less than what the manufacturer recommends. 

What about plants?

Well, I have a theory about plants and tannins...

First off, as you know by now, you absolutely can keep plants in blackwater aquariums. We've talked about this a million times over the years. And yet,  interestingly, you can't always keep "blackwater conditions" (at least, color-wise) in planted aquariums! There has been much geeky discussion on this topic.

Tannin are interesting things. Think about this:

Tannins are known to bind up heavy metals and minerals. The roots of aquatic plants prefer to take up bound-up minerals and metals...So, another theory of mine is that heavily planted tanks do actually remove some of the visual "tint" (ie; the tannins) from the water via uptake from their roots. 

Make sense? Maybe?

Okay, I could go on and on all day throwing out all sorts of theories and unsubstantiated (via lab tests and rigorous studies, anyways) ideas on this topic...But I think I gave you enough here to get the party started. I encourage you to do some homework. We need to ask these questions to people who really understand the chemistry here. I think that there might be some good answers out there.

And, back to the "color thing" to close on here...

I admit, visual "tint" is probably THE single most superficial aspect of what we experience with botanical-method aquariums- but the most obvious, and likely the most impactful to the casual hobbyist or observer.

It's just as important to understand the collateral benefits of utilizing botanical materials- a subject we've discussed dozens of times here. However, in the end, it's the look of your aquarium that is what you have to experience each and every day, and if having an understanding of which materials can bring you the aesthetic experience you're after in a more effective way- well, then this is a worthwhile discussion, right?

I think that it is.

Stay curious. Stay resourceful. Stay enthusiastic. Stay observant. Stay appreciative. Stay tinted...

And Stay Wet.


Scott Fellman

Tannin Aquatics  

Anything goes? Well, sort of...

The garden suggests there might be a place where we can meet Nature halfway."-Michael Pollan

It's long been suggested that an aquarium is sort of like a garden, right? And, to a certain extent it is. Of course, we can also allow our tanks to evolve on a more-or-less "random" path than the word "garden" implies...

Perhaps one of the most liberating things about our botanical-method aquariums is that there is no set "style" that you have to follow to "arrange" botanical materials in your tank. 

When you look at those amazing pictures of the natural habitats we love so much, you're literally bombarded with the "imperfection" and apparent randomness that is Nature. Yet, in all of the "clutter" of an igarape flooded forest, for example, there is a quiet elegance to it. There is a sense that everything is there for a reason- and not simply because it looks good. It IS perfect. Can't we bring this sense to our aquariums?

I think we can...simply by meeting Nature halfway.

To a certain extent, it's "anything goes" in terms of adding materials to represent the wild habitats. I mean, when you think about flooded forest floors and rainforest streams, you're talking about an aggregation of material from the forest that has accumulated via wind, rain, and current. The influences on the "design" are things like how something arrives into the water, and how it gets distributed by water movement. 

Nature offers no "style guide." 

Rather, she offers clues, based on her processes.

I mean, sure, you could and should certainly use some aesthetic thought in the concept, but when you're trying to recreate what in Nature is a more-or-less random thing, you probably don't want to dwell too much on the concept! You don't want to over-think "random" too much, right? Rather, put your effort into selecting suitable materials with which to do the job.

For a bit more context, just think for just a second, about the stems and branches that we love so much in our aquascaping. Those of us who obsessively study images of the wild tropical habitats we love so much can't help but note that many of the bodies of water which we model our aquariums after are filled with tree branches and stems.

Since many of these habitats are rather ephemeral in nature, they are only filled up with water part of the year. The remainder of the time, they're essentially dry forest floors.

And what accumulates on dry forest floors?

Branches, stems, leaves, and other materials from trees and shrubs. When the waters return, these formerly terrestrial materials become an integral part of the (now) aquatic environment. This is a really, really important thing to think of when we aquascape or contemplate how we will use botanical materials like the aforementioned stems and branches.

They impact both function and aesthetics of an aquarium...Yes, what we call "functional aesthetics" rears its head again!

There is no real rhyme or reason as to why stuff orients itself the way it does once submerged. There are numerous random factors involved. 

I mean, branches fall off the trees, a process initiated by either rain or wind, and just land "wherever." Which means that we as hobbyists would be perfectly okay just literally tossing materials in and walking away! Now, I know this is actually aquascaping heresy- Not one serious 'scaper would ever do that...right?

On the other hand, I'm not so sure why they wouldn't! 

I mean, what's wrong with sort of randomly scattering stems, twigs, and branches in your aquascape? It's a near-perfect replication of what happens in Nature. Now, I realize that a glass or acrylic box of water is NOT nature, and there are things like "scale" and "ratio" and all of that shit that hardcore 'scapers will hit you over the head with...

But Nature doesn't give a fuck about some competition's "rules"- and Nature is pretty damn inspiring, right? There is a beauty in the brutal reality of randomness. I mean, sure, the position of stones in an "Iwagumi" is beautiful...but it's hardly what I'd describe as "natural."

Natural looks...well, like what you'd see in Nature.

It's pretty hardcore stuff.

And it's all part of the reason that I spend so damn much time pleading with you- my fellow fish geeks- to study, admire, and ultimately replicate natural aquatic habitats as much as you do the big aquascaping contest winners' works. In fact, if every hobbyist spent just a little time studying some of these unique natural habitats and using them as the basis of their work, I think the hobby would be radically different.

When hobbyists interpret what they see in wild aquatic habitats stats more literally, the results are almost always stunning. And contest judges are starting to take notice...

I think that there would also be hobby success on a different level with a variety of fishes that are perhaps considered elusive and challenging to keep. Success based on providing them with the conditions which they evolved to live in over the millennia, not a "forced fit" its what works for us humans.

More awareness of both the function and the aesthetics of fascinating ecological niches, such as the aforementioned flooded forests, would drive the acceptance and appreciation of Nature as it is- not as we like to "edit" and "sanitize" it.

Taking this approach is actually a "stimulus" for creativity, perhaps in ways that many aquarists have not thought of. 

There are a lot of aquatic habitats in Nature which are filled with tangles of terrestrial plant roots, emergent vegetation, fallen branches, etc., which fill small bodies of water almost completely.

These types of habitats are unique; they attract a large populations of smaller fishes to the protection of their vast matrix of structures. Submerged fallen tree branches or roots of marginal terrestrial plants provide a large surface area upon which algae, biofilm, and fungal growth occurs. This, in turn, attracts higher life forms, like crustaceans and aquatic insects. Sort of the freshwater version of a reef, from a "functionality" standpoint, right?

Can't we replicate such aquatic features in the aquarium?

Of course we can!

This idea is a fantastic expression of "functional aesthetics." It's a "package" that is a bit different than the way we would normally present an aquarium. Because we as hobbyists hesitate to densely pack an aquarium like this, don't we?

Why do you think this is?

I think that we hesitate, because- quite frankly- having a large mass of tangled branches or roots and their associated leaves and detritus in the cozy confines of an aquarium tends to limit the number, size, and swimming area of fishes, right? Or, because its felt that, from an artistic design perspective, something doesn't "jibe" about it...

Sure, it does limit the amount of open space in an aquarium, which has some tradeoffs associated with it.

On the other hand, I think that there is something oddly compelling, intricate, and just beautiful about complex, spatially "full" aquatic features. Though seldom seen in aquarium work, there is a reason to replicate these systems. And when you take into account that these are actually very realistic, entirely functional representations of certain natural habitats and ecological niches, it becomes all the more interesting!

What can you expect when you execute something like this in the aquarium?

Well, for on thing, it WILL take up a fair amount of space within the tank. Of course. Depending upon the type of materials that you use (driftwood, roots. twigs, or branches), you will, of course, displace varying amounts of water.

Flow patterns within the aquarium will be affected, as will be the areas where leaves, detritus and other botanical materials settle out. You'll need to understand that the aquarium will not only appear different- it'll function differently as well. Yet, the results that you'll achieve- the more natural behaviors of your fishes, their less stressful existence- will provide benefits that you might not have even realized possible before. 

This is something which we simply cannot bring up often enough. It's transformational in our aquarium thinking. 

The "recruitment" of organisms (algae, biofilms, epiphytic plants, etc.) in, on, and among the matrix of wood/root structures we create, and the "integration" of the wood into other "soft components" of the aquascape- leaves and botanicals is something which occurs in Nature as well as in the aquairum.

This is an area that has been worked on by hobbyists rather infrequently over the years- mainly by biotope-lovers. However, embracing the "mental shifts" we've talked about so much here- allowing the growth of beneficial biocover, decomposition, tinted water, etc.- is, in our opinion, the "portal" to unlocking the many secrets of Nature in the aquarium.

The extraordinary amount of vibrance associated with the natural growth on wood underwater is an astounding revelation. However, our aesthetic sensibilities in the hobby have typically leaned towards a more "sterile", almost "antispetic" interpretation of Nature, eschewing algae, biofilm, etc.

However, a growing number of hobbyists worldwide have began to recognize the aesthetic and functional beauty of these natural occurances, and the realism and  I think that the intricate beauty of Nature is starting to eat away at the old "sterile aquascape" mindset just a bit!

And before you naysayers scoff and assert that the emerging "botanical method" aquarium is simply an "excuse for laziness", as one detractor communicated to me not too long ago, I encourage you once again to look at Nature and see what the world underwater really looks like. There is a reason for the diversity, apparent "randomness", and success of the life forms in these bodies of water.

What is it?

It's that these materials are being utilized- by an enormous community of organisms- for shelter, food, and reproduction. Seeing the "work" of these organisms, transforming pristine" wood and crisp leaves into softening, gradually decomposing material, is evidence of the processes of life.

When you accept that seed pods, leaves, and other botanical materials are somewhat ephemeral in nature, and begin to soften, change shape, accrue biofilms and even a patina of algae- the idea of "meeting Nature halfway" makes perfect sense, doesn't it? 

You're not stressing about the imperfections, the random patches of biofilm, the bits of leaves that might be present in the substrate. Sure, there may be a fine line between "sloppy" and "natural" (and for many, the idea of stuff breaking down in any fashion IS "sloppy")- but the idea of accepting this stuff as part of the overall closed ecosystem we've created is liberating.

Sure, we can't get every functional detail down- every component of a food web- every biochemical interaction...the specific materials found in a typical habitat- we interpret- but we can certainly go further, and continue to look at Nature as it is, and employ a sense of "acceptance"- and randomness-in our work. 

I'm not telling you to turn your back on the modern popular aquascaping scene; to disregard or dismiss the brilliant work being done by aquascapers around the world, or to develop a sense of superiority or snobbery, and conclude that everyone who loves this stuff is a sheep...


Not at all.

I'm simply the guy who's passing along the gentle reminder from Nature that we have this great source of inspiration that really works! Rejoice in the fact that Nature offers an endless variety of beauty, abundance, and challenge- and that it's all there, free for us to interpret it as we like. Without aesthetic rules, rigid standards, and ratios. The only "rules" are those which govern the way Nature works with materials in an aquatic environment.

A botanical-method aquarium features, life, death, and everything in between.

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

But mainly, to Nature.

The processes of life which occur within the microcosm we create are indifferent to our desires, our plans, or our aspirations for it. Sure, as humans, we can influence the processes which occur within the aquarium- but the ultimate outcome- the result of everything that we did and did not do- is based solely upon Nature's response.

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

It's a beautiful process. Seemingly random, yet decidedly orderly.

Think about that for a bit.

Stay curious. Stay bold. Stay creative. Stay thoughtful...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Throwing some light on blackwater...

It goes without saying that the single most important component of our aquariums is also the most obvious...water! As the literal bearer of life and the environment in which our fishes, plants, and other organisms thrive, it's fundamental. it's the reason we're drawn to fishes, not gerbils, Tarantula, or Mice- or whatever other pets people keep!

Yeah, we're into water!

And I dear say that we take it for granted a bit.

Now, sure, some hobbyist rightfully place the importance of good quality, properly-conditioned water at the very top of their "want list" of "Stuff" required for successful aquariums. These are often fish breeders and very serious hobbyists, who understand the fundamental importance of good water for their work.

Some of the most common questions we receive lately are "How much _______ do I need to get my water to look like________?" or "How much_______ is needed to lower the pH in my tank?" Or, "How much do I need to get a good amount of humic substances and tannins into my aquarium?"

I usually respond with a simple, "I don't know."

These are all really good questions. Logical. Important.  I kind of feel like many hobbyists are looking for a plug-and-play "formula" or "recipe" for how to accomplish certain water-conditioning tasks.

I totally get that. But the reality is...there IS no "recipe" for how to do this stuff.

And it sucks, I know.

"Why, Scott? I read that you can just add some of this blackwater extract that you can buy online, and maybe add some catappa leaves, and..."

Stop. STOP. Please, we're just making this painful.

Simply adding leaves or bottled extracts to your tap water isn't going to result in "Instant Amazon" or whatever. There are numerous complexities and nuances which contribute to these habitats that to simply recommend adding "X" to your water isn't the whole story.

There are so many variables in the equation that it's almost impossible to give a definitive answer. And yeah, us guys in the botanical biz haven't really helped the situation. Over the years, vendors who sold catappa leaves, for example, would recommend starting amounts ("three leaves per 15 liters of water" or whatever...) of botanical materials to use in aquariums.

I mean, we've sort of done it, too...And, although our recommended "dosage" of leaves was given for different reasons (to avoid adding too much material to your tank too quickly), the idea of a "recipe" in general is kind of delusional, IMHO.

Now, this was all well and good, but it's based on....what? I mean, is this based on how many leaves of _______ size that a typical hobbyist with a 10-gallon aquarium needs to get the water "looking brown?" Or to lower tap water with a starting pH of 7.4 and a KH of ___ to pH of 6.9? Or to impart "x" ppm of tannins or humic substances into this given quantity of water?

See? Add to this story the fact that you really can't soften water and make it more "malleable" by using botanicals or extracts alone, and you've got a good case for confusion! It's just not that simple.

Maybe we can gain a bit of understanding- or at least, an appreciation for the dynamics of this process, by looking once again to Nature.

Have you very thought about how water reaches all of the wild aquatic systems of the world? I mean, it's got to get there some way, right? So, how does it reach the ponds, lakes, streams, and rivers and forest floors of the world?

Well, some simply falls into the body of water directly from the sky, and that's that. Some is a result of other overflowing streams and rivers (like, ya' know- those flooded Igapo forests we talk about!). Inputs of precipitation falling over the area of an aquatic habitat are transferred to the habitat via a number of different pathways.

It's surprisingly complicated.

There's like a whole field of science devoted to studying this process! It's called Hydrology, and it's incredibly interesting...As fish geeks, we're probably already acquainted with this field of study, at least tangentially! 

So, water comes from a variety of sources, reaching a myriad of ecological niches. However, not all of the water has such an easy journey on its way into our favorite aquatic habitat!

Even in the case of rainwater, some of it simply lands on tree leaves in the surrounding area and evaporates. This is a process scientists call "interception", and accounts for the fact that not all water makes it to the ground. Water that does reach the ground enters the soil through a process called infiltration. slowly percolating down to soil areas known as the "saturated zone"- and as you'd imagine, this is where the fun really begins! (to a soil geologist, at least!)

The soil properties control the infiltration capacity; these include things like soil permeability, the presence of vegetation and plant roots, and how much water is already in the soil. Through what is known as "ground water flow", ultimately, the water finds it way into our favorite aquatic habitats. It's important to note that soil texture ( the relative proportion of sand, silt and clay particles within the mix) affects infiltration rates. 

Sandy soils like the "podzols", common to forested areas of South America that we've talked about have higher permeability than some clay-based soils. In some really arid areas a "crust" can form on the soil surface, decreasing the permeability. And of course, the thickness of the soil directly affects how much water the soil can actually absorb.

And, in many cases, the substrate composition and its relationship with water has direct impact on the life forms which inhabit these aquatic systems. In the case of some habitats, like vernal pools, which are filled with water seasonally, the substrate is of critical importance to the aquatic life forms which reside there.

Yeah, soils and geology are perhaps the primary driver of water composition in Nature. 

Let's talk more about "blackwater."

In a blackwater environment, the color is a visual indicator of an influx of dissolved materials that contribute to the "richness" of the environment. Indeed, a blackwater environment is typically described as an aquatic system in which vegetation decays, creating  tannins that leach into the water, making a transparent, acidic water that is darkly stained, resembling tea.

But, that's not the whole story, really.

It’s important to really try to understand the most simple of questions- like, what exactly is “blackwater”, anyways?

A scientist or ecologist will tell you that blackwater is created by draining from older rocks and soils (in Amazonia, look up the “Guyana Shield”), which result in dissolved fulvic and humic substances, present small amounts of suspended sediment, and characterized by lower pH (4.0 to 6.0) and dissolved elements, yet higher SiOcontents. Magnesium, Sodium, Potassium, and Calcium concentrations are typically very low in blackwater. Electrical conductivity (ORP) is also lower than in so-called "whitewater" habitats.

Tannins are also imparted into the water by leaves and other botanical materials which accumulate in these habitats.


The action of water upon fallen leaves and other botanical-derived materials leaches various compounds out of them, creating the deep tint that many of us are so familiar with. Indeed, this "leaching" process is analogous to boiling leaves for tea. The leached compounds are both organic and inorganic, and include things like tannin, carbohydrates, organic acids, pectic compounds, minerals, growth hormones, alkaloids, and phenolic compounds.

Most of the of the extractable substances in the surface litter layer are humic acids, typically coming from decaying plant material. Scientists have concluded that greater input of plant litter leads to greater input of humic substances into ground water.

In other words, those leaves that accumulate on the substrate are putting out significant amounts of humic acids, as we've talked about previously! And although humic substances, like fulvic acid, are found in both blackwater and clear water habitats, the organic detritus (you know, from leaves and such) in blackwater contains more extractable fulvic acid than in clearwater  habitats, as one might suspect!

The Rio Negro, for example, contains mostly humic acids, indicating that suspended sediment selectively adsorbs humic acids from black water.  The low concentration of suspended sediments in rivers like the Rio Negro is one of the main reasons why high concentrations of humic acids are maintained. With little to no suspended sediment, there is no "adsorbent surface" (other than the substrate of the river, upon which these acids can be taken hold of (adsorb).

When you think about it, all of this this kind of contributes to why blackwater has the color that it does, too. Blackwater in the Amazon basin is colored reddish-brown. Why? Well, it has  those organic compounds dissolved in it, of course. And most light absorbtion is in the blue region of the spectrum, and the water is almost transparent to red light, which explains the red coloration of the water!

And many of those organic compounds come from the surrounding land, as touched on above...

In summary, natural "blackwaters" typically arise from highly leached (tropical) environments where most of the soluble elements in the surrounding rocks and soils are rapidly removed by heavy rainfall. Materials such as soils are the primary influence on the composition of blackwater.

Leaves and other materials contribute to the process and appearance in Nature, but are NOT the primary “drivers” of its creation and composition.


So, right from the start, it’s evident that natural blackwater is “all about the soils…” Yeah, I'll repeat it again: It’s more a product of geology than just about anything else. 

More confusing, recent studies have found that most of the acidity in black waters can be attributed to dissolved organic substances, and not to dissolved carbonic acid. In other words, organic acids from compounds found in soil and decomposing plant material, as opposed to inorganic sources. Blackwaters are almost always characterized by high percentages of organic acids.

Despite the appearance, as a general rule, blackwater rivers are lower in nutrients than clear rivers. Wouldn't it be interesting, when contemplating more natural biotope/biotype aquariums, to study and take into consideration the surrounding geology and physical characteristics of the habitat?  Too recreate the habitat based on the soil or geological composition of the surrounding terrestrial environment?

As we know now, the influence of factors like soil, and the presence of terrestrial materials like seed pods, leaves, and branches play a huge role in the chemical composition and appearance-of the water. It's really no different in the aquarium, right?

Like so many things in nature, the complexity of blackwater habitats is more than what meets the eye. Chemically, biologically, and ecologically, blackwater habitats are a weave of interdependencies- with soil, water, and surrounding forest all functioning together to influence the lives of the fishes which reside within them. No single factor could provide all of the necessary components for fish populations to thrive.

To damage or destroy any one of them could spell disaster for the fishes- and the ecosystem which supports them. It is therefore incumbent upon us to understand, protect, and cherish these precious habitats, for the benefit of future generations. 

And with regards to our aquarium work?

Although there may even be breakthroughs in terms of blackwater extracts and additives coming to market, there are still a lot of questions that would have to be answered before we could simply state that "X" drops per gallon of such an such a formula would yield a specific outcome. This reminds me of the reef aquarium world more an more, lol.

So, if I've made any "argument" here, it's that this stuff is every bit as much of an "art"- in terms of aquarium keeping- as it is a "science." We will, at least for the foreseeable future, have to use the data we have available and formulate a best guess as to how much of what can give us some of the impacts we are interested in for our aquariums.

We simply can't authoritatively make blanket statements like, "You need to use "X" catappa leaves per gallon in order to recreate Rio Negro-like conditions in your aquarium!" We can't simply state that you can throw in some podzolic soil and achieve blackwater, either. There are many factors in play, as we've discussed here, right?

Marketing hyperbole aside, we really are sort of...guessing.

And that's certainly nothing to be discouraged about!

We, as a community, are getting deeper into the functional aspects of blackwater, botanical-style aquariums than ever before. More light is being shed on what's going on in both our aquariums and in the natural habitats we desire to replicate. We are learning more every day about how the presence of tannins and humic substances in our aquariums is affecting the health, longevity, and spawning behaviors of our blackwater fishes.

We're learning about the challenges and realities of managing blackwater systems over the long term- understanding the good, the bad, and the dangerous possibilities that are present when we experiment with these ideas.

There is much, much more work to be done..And a lot of talented hobbyists like yourself are out there on the front lines every day, contributing to the body of knowledge that will benefit the hobby for generations!

Stay persistent. Stay bold. Stay open-minded. Stay curious. Stay disciplined...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


The hobby is easy, right?

Today. I'm sort of taking a contrary stance to what you might typically see in aquarium blogs. Okay, what else is new, right?

My position is this: The aquarium hobby, while not "difficult", is not super easy, either. And quite honest, it shouldn't be super easy. And we shouldn't be 'dumbing it down' so much.

Uh-ohh. Controversy time.

Well, before you go and label me a jackass and pelt me with "Hakkai Stones", think about it: We are creating and managing the entire environment for specialized living creatures. Unlike a dog or cat, which (at the risk of over simplifying things) just needs food and a place to sleep to survive, fishes require a place to live, the proper aquatic environment, including heat, nutrient export, food, oxygenation, and light. We also are responsible for creating a compatible community of animals, understanding the dynamics of the nitrogen cycle, quarantine, acclimation, disease identification and treatment, and a lot more.

Sure, having to master all of these that I things listed out makes it sound like we're freaking genius-level people to be successful. We don't have to be, of course (I mean, look at some of the clowns who are YouTube “influencers” and the drivel they generate...😂)- but we do have to understand and be able to execute successfully on a number of fronts in order not to kill our fishes immediately, don't we?

Now, a little bit of props to the fishes themselves! I mean, they're subjected to a lot of shit before they get to us, right? Wild fishes, especially, undergo a real trial just to get to us: Collection, sorting by the fishers, a few days at a exporter's facility, a flight from their home country, a stint at a wholesaler, then on to the LFS, and finally to you. All the while, adapting to varying conditions, crowding, and little, if any food. When you think about it, it's hard to believe that they survive at all!


Back to our gig.

As hobbyists, we're morally obligated to have at least a rudimentary understanding of the requirements which our fishes need to survive and thrive. And, unfortunately, in today's "Insta-fast"  "Everyone can go from zero to hero in three days" social-media-driven hobby, many hobbyists simply don't have that. In fact, if you asked 10 hobbyists some of the most basic aquarium-related questions, such as how the nitrogen cycle works, or what pH means, I'll wager that you'd likely get 3-4 hobbyists who couldn't articulate anything about these topics.

However, if you ask them about the best aquascaping rock, trendy approach, or stupidly-named wood type, I'll bet they'll be able to tell you everything you'd care to know.

That's indicative of a problem. When we accept this level of mediocrity, we're making ignorance of the art and science of aquarium keeping cool.

That's crazy.

We're better than this.

We as hobbyists need to educate ourselves before we leap. Now, at this point, there are likely a few readers/listeners who will be like, "Damn, Captain Buzzkill, you're making it like you have to be a freaking marine biologist to be able to keep tropical fish! WTF?"

My response?

No, I'm not. And pointing out reality doesn't make me a complete asshole. Well, sort of an asshole- but not a complete one! 😆

Seriously, though, there is something really wrong when we have hobbyists trying all sorts of crazy expensive and exotic hobby ideas and equipment, when their fundamental understanding of the aquarium hobby is essentially inadequate.

Like, we've created a generation of hobbyists who want to run before they can walk. They're always looking for "hacks" and shortcuts for "making things easier." And when they fail- they have no way to understand why. And they often quit the hobby as a result. I've seen this dozens of times during my hobby "career." And we- the industry, creators, and communicators of the aquariums hobby- are responsible for this.

Now look, I'm all for making things easier, but NOT for dumbing down stuff. It shouldn't be like having to take board examinations in order to keep a fish tank, and setting up and caring for a tank shouldn't always be onerous- but you should at least try to have a working knowledge of a bunch of fundamental topics before you plunk down your cash and put fishes' lives on the line, right? And you should want to. And we as hobbyists should be interested in learning and acquiring the basic skills necessary to assure a good start in the hobby. We don't need to make this a task; we just need to do a little basic research first. 

This is where the local fish store can excel.

The "mentoring" you can receive from a quality fish store is one of the best first exposures you can have to the art and science of aquairum keeping. As long as they don't take a purely sales-oriented approach to things (and most don't, despite the popular, persistent hobby mythology of the buffoonish, ignorant, and predatory LFS personnel that have been the stuff of online lore for decades now). Most LFS staff are uber hobbyists, obsessed with aquariums and fishes, and have a vested interest in seeing their customers succeed.

For those who need to get their "education" online, there are a lot of good resources. I don't need to rehash that. However, despite its popularity and search ability, YouTube isn't always the best source. There ARE a lot of great channels out there, but there is also a disproportionately high number of outright garbage, too. Channels in which the "creator" seems to have absolutely no clue about the topic he/she is authoritatively spewing. In our own sector alone, I've seen this several times. It's vomit inducing. 

And a lot of the stuff out there- even "sponsored content"- is about drivel...doing a certain scape with this cool rock, or how to arrange wood so that your tank looks like everyone else's', or something equally as vapid. There is proportionately little produced about fundamental hobby stuff.

We can't run from some of the science stuff...I mean, we are ALL at the mercy of the nitrogen cycle, for example, and we need to have at least a basic understanding of how it works and what the implications are for our aquarium work. It's actually really important!

When I co-owned a coral propagation/import business, a scarily high percentage of the questions from customers were frighteningly basic- like stuff you should know before you ever even buy any aquarium, let alone set up a reef tank.


Back in those days, I literally received calls from hobbyists who didn't have the most rudimentary understanding of the needs of corals, let alone, the nitrogen cycle- yet they spent tens of thousands of dollars outfitting their reef tank with the latest gear, and buying the latest "designer frags."

it was head-scratching, to say the least. It was downright discouraging on some days.

It's not just limited to the reef world, of course. It’s all over the hobby. 

And, it's our fault as an industry, too.

We seem to sell prepackaged "solutions" for everything. Another piece of gear, another additive..."That'll solve your problems!" We seem to be happier just selling people a product that we hope will solve their problems. Laughably, I've seen soem vendors/manufacturers trot out the pathetic line about their product making things easier so you could "enjoy the hobby more!" Like, WTF? Isn't feeding your fishes, doing water exchanges, and just managing the tank part of what makes it enjoyable, too? Or is the only enjoyable part of the hobby humble-bragging on The 'Gram about our latest aquascape?

How about we educate people on the basics and beyond? The good, the bad, and the shitty? That will make the use of your product a lot more logical. Yet, I know- it takes time. It's more difficult to educate people on the underlying problem...the reason why people would need your product in the first place. It's much easier to just tell them what to buy and that's that. It sells stuff faster. But it doesn't build a long-term hobbyist. That's why we at Tannin have article after article on the most basic, and even arcane aspects of playing with blackwater/botanical-style aquariums on our site.

Because I believe that hobbyists have to be armed with the most fundamental knowledge of our craft in order to succeed. I'm not going to just show pretty pics of cool 'scapes and sell seed pods and leaves that way. That's how I'm going to do my part to address the hobby dropout thing. My friends James of Blackwater UK and Ben of Betta Botanicals, two vendors as geeked out as I am about this stuff, are on the same page as me. We're determined to show hobbyists that the process- the whole thing- is as much fun as just looking at the number of likes your tank pics get on your fave social media channel.

It's a wider hobby "cultural problem", too. We're lazy. A lot of us want instant gratification and simply don't want to take the time to dig through information- even if it's out there in abundance. They want it easier. Faster. More concise.

And yes-I know. Everyone is "busy", etc. Yet, why have a hobby in the first place if you don't want to spend time playing with it and educating yourself about it? People can't be lazy. They have to learn the underlying, fundamental stuff. They need to read, watch, discuss, observe. A personal example again? I get numerous emails asking me how to prepare botanicals- even after we spent hundreds and hundreds of dollars on producing a customized infographic card that goes in every order, and years writing dozens of articles on this very topic.

Some people seem so unwilling to do the most basic research! What a shame.  I mean, Google is one of the greatest inventions in the history of humanity, making information about virtually any topic imaginable available anywhere, any time, to anyone. Easily.

Yet, many figure the "hack" is just to ask someone and expect them to give concise answers on how to do everything, instead of taking the extra time to educate themselves a bit before just mailing it in and prodding someone else for the answer. Yeah, we've somehow decided that a DM to someone for a “quick answer” is a better way to acquire knowledge than typing in the keywords, like "what is the nitrogen cycle?" and learning it once and for all. 

Obviously, as an industry guy and writer- I'm always going to help those with questions when I can...But I also need to encourage self-research, too. I still need to do better at disseminating information. We all do.

There's blame enough to go around. And to newbies and others in the hobby-my plea to you:

Don't be freaking lazy. The resources are there.

We just have to keep directing people towards them. And people need to use them. And we have to emphasize the fundamentals of the hobby. Not just the cool creative stuff. Sure, not everyone is great at conveying technical concepts to people in an easy-to-understand manner. However, we can try, Because, when no one is doing that, we end up with 14,000 channels on how to "scape a blackwater aquairum" and not a single one explaining what the hell blackwater is, and how to manage the ecology of a blackwater system.

That's a problem, IMHO.

Everyone wants to do the "fun" stuff, hype their sponsors' products, and get all of that recognition. Yet, without discussing the less sexy fundamentals, the "fun stuff" just becomes a waste of precious animal lives and lots of money. People get frustrated and quit the hobby. When I see the words "paid partnership" under an Instagram post lately, I almost reflexively (and often correctly, I'm afraid) assume that it's usually drivel. Because most of the creators- and the brands who sponsor them- have accepted a level of superficiality as the norm. And that's really sad. These people are too talented to waste their followers' precious attention- and their sponsor's money- by producing such mindless fluff.

The "creative" and "trendy" is valued over the substance, even by brands. And the irony is that doing a little more substance in a creative manner is what will sell more product and build a stronger brand in the long run. Yet, it's easier to just pay some "creator" do a fun little video with a bit of hip-hop music, the appropriate sponsor hashtags, and consider it a job well done.

I call bullshit on that.

Brands need to stop paying these "creators" for this garbage.

You can still be creative and edgy and cool while conveying complex or arcane topics... Hell, we do it all the time here (so modest, right?).

Yes, even in the social media "Insta-hype" world we're in, there is room for improvement. I've hit this hard before...we all show too much "finished product" with killer aquascapes and such, and not enough of the less sexy, although way more important process...

There is an easy fix for that one. Just share the process. 

Discuss the fundamentals of what you do.

When hobbyists realize it's not just "1-2-3 AWESOME!"- and that there is a little work, and occasional setbacks and struggle involved, expectations are set which assure people go in with their eyes wide open...and stay in. Expectation management via education. And there is a certain responsibility that we as hobbyists take on when keeping live fishes; this needs to be emphasized.  And guess what, fellow aquarium brands? They'll still buy your product. In fact, they'll probably be more likely to, because they will have a fundamental understanding for why they need it.

No. The aquarium hobby isn't that easy.

But it's not ridiculously hard, either. 

We have a responsibility as hobbyists to keep these precious creatures alive and happy. And we as hobby and industry people have an obligation to tell it like it is. To touch on fundamentals. To explain things. To convey that, while not overly complex, some the underlying information that you need to know to be successful in the hobby is vital. Even if it requires a bit of reading and discussion in order to grasp it. And that it's every bit as interesting as selecting the right stones for your next fantasy 'scape.

In our world, there is a reason why we talk so much about ecology and arcane things, like the idea of allochthonous input into wild aquatic habitats. There is a reason why we devote hundreds of thousands of words to subjects like fungi, biofilms, and detritus. It's because an understanding of these topics is foundational to the work we do as botanical-style aquarium enthusiasts. When you understand these things, you're better equipped to understand what's happening in your aquairums. 

It would have been much easier for me if I spent the last 6 years writing articles and doing podcasts on how to get the sexy look of a botanical-style aquarium. Yet, it would have left us simply another hollow, vapid purveyor of leaves and seed pods, passing the buck to someone else to cover these ideas, develop the operating fundamentals and philosophies which are applicable to the botanical-style aquarium methodology.

Not on my watch.

I'm going to continue discussing some of these seemingly arcane topics. Why? Well, for several reasons. First, because someone has to do it. Might as well be me; I play with this stuff every day of my life. Second, because it's so important to convey these fundamentals. It builds a movement and reinforces the methodology we all embrace. Third, because I feel that I have a responsibility to the hobby, and to the fishes we love. And finally, because it's hard. It's not easy to distill these complex ideas into digestible information. And that very fact makes it a worthwhile endeavour.

We all need to learn, understand, and share these types of topics.

Success in the aquarium hobby isn't that difficult- after you have a grasp of the fundamentals; an understanding of why we do what we do. However, the hobby isn't "easy" in the sense that you just toss your fishes into the water and call it a day. It takes some work. It should take some work. Because taking care of live animals, some of which are threatened in the wild, is a huge responsibility which should not be taken lightly.

So, maybe the tone of this piece is a little bit dark to some. It shouldn't be interpreted that way. Rather, it's a brutally honest call for us to make a better effort to understand and appreciate just how amazing what we as aquarists do every dingle day, and what responsibility goes along with these achievements. It's a call to wake up- look ourselves in the mirror as hobbyists, content creators,  and industry types- and do better.

We can. There is enormous talent out there- and there has never been a time in history when its easier to disseminate useful information to a larger number of interested persons. 

We just have to DO it. To not shirk this responsibility- and this gift.

It's not as hard as you think, and the benefits of the effort are remarkable.

Stay honest. Stay reflective. Stay creative. Stay observant. Stay inspired...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



Accumulating botanical materials...and mental toughness!

They say that Nature abhors a vacuum...

Nature also seems to like to accumulate stuff, doesn't it? 

Natural watercourses are really good at accumulating terrestrial materials, creating inviting habitats for fishes. They serve not only as physical locales for fishes to forage an hide amongst, they provide a huge habitat for a variety of other organisms which support the fishes.

And of course, these are compelling aquatic features for us fish geeks to replicate in our aquariums, aren't they? They are, and perhaps provide the basic "role model" for the botanical-style aquairum.

These aggregations of materials occur all the time in Nature, and they're caused by a variety of things; typically, weather events, which drive materials off of the trees overhead, or from the surrounding terrestrial habitats into the water. Currents caused by rising water levels move the materials along, until they might be caught up among various benthic features, like fallen trees, branches, rocks, etc.

Yeah, as you'd imagine, stream and river bottom composition is completely affected by things like weather, current, geology, the surrounding terrestrial habitat, and a host of other factors- all of which could make planning your next aquarium even more interesting if you take them into consideration! 

According to one study I read, eventually, most of the organic debris is deposited on the stream bottom or drifts downstream until it becomes trapped by a variety of natural obstacles.

If we focus on streams, it's important to note that the volume of water entering the stream, and the depth of the channels it carves out, helps in part determine the amount and size of materials which accumulate, as well as the sediment particles that can be carried along, and thus comprise the substrate of this habitat. .

And of course, the composition of bottom materials and the depth of the channel are always changing in response to the flow in a given stream, affecting the composition and ecology in many ways.

Some leaf litter beds form in what stream ecologists call "meanders", which are stream structures that form when moving water in a stream erodes the outer banks and widens its "valley", and the inner part of the river has less energy and deposits silt- or in our instance, leaves.

There is a whole, fascinating science to river and stream structure, and with so many implications for understanding how these structures and mechanisms affect fish population, occurrence, behavior, and ecology, it's well worth studying for aquarium interpretation!  Did you get that part where I mentioned that the lower-energy parts of the water courses tend to accumulate leaves and sediments and stuff?

Likely you did!

Permanent streams will often have different volume and material composition (usually finely-packed sands and gravels, with lots of smooth stones) than more intermittent streams, which are the result of inundation caused by rain, etc.

So-called "ephemeral" streams, typically occur only immediately after rain events (which means they usually don't have fish in them unless they are washed into them from more permanent watercourses). The latter two stream types are typically more affected by leaves, botanical debris, branches, and other materials.

In the Amazon region (you knew I was sort of headed back that way, right?), it sort of works both ways, with the rivers influencing the surrounding land...and then the land "giving" some of the materials back to the rivers...the extensive lowland areas bordering the river and its tributaries, known as varzeas (“floodplains”), are subject to annual flooding, which helps foster enrichment of the aquatic environment.

Land and water, working together, provide and amazing resource for the adventurous and interested hobbyist to explore in greater detail.

The important, and overriding Thieme of many aquatic habitats which we try to replicate in the hobby is that they accumulate quantities of terrestrial materials. These materials don't just impact the physical characteristics of these habitats, they influence the ecology as well. As we know by now, terrestrial materials, when submerged in water, leach soluble compounds into the water, impacting the chemistry.

They also tend to recruit fungal growths and biofilms, which in turn serve to not only decompose the terrestrial materials- they tend to attract fishes to graze upon them! Terrestrial materials form the basis of a rich, surprisingly complex aquatic ecology. A food web arises.

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.

Interestingly, in streams, the primary producers of the food webs that attract our fishes are...algae and diatoms, which are typically found on rocks and wood wherever light and nutrients create optimum conditions for their growth. Organic material that enters streams via leaf fall is acted upon by small organisms, which help break it down.

It is probably no surprise, then, that bacteria (especially in biofilms!) and fungi are the initial consumers of the organic materials that accumulate on the bottom. Like, the stuff many of us loathe. These, in turn, are extremely vital to fishes as a food source. Hence, one of the things I love so much about utilizing a leaf litter bed as a big part of your substrate composition in an aquarium!

We are able to establish rudimentary food webs in our aquariums. It's pretty easy, if we don't try to clean the crap out of our tanks and remove every bit of organic matter which we deem offensive to our aesthetic sensibilities! Remember, all of that material which we freak out about is someone's next meal, isn't it? It's consumed. The various organisms which arise when we allow leaves, branches, seed pods and other materials to accumulate and decompose in our tanks help see to that.

Yes, aquariums are different than wild aquatic habitats, but they have many characteristics which are analogous to them. And, sure, we typically don't maintain completely "open" systems, but I wonder just how much of the ecology of these fascinating habitats we can replicate in our tanks-and what potential benefits may be realized?

I'm willing to bet that it's a lot more than we think. However, we have to start somewhere, right?

It all starts with adding and accumulating terrestrial materials in our tanks, and allowing an ecology to grow up around them. It's that simple- and that complex, right? It falls on us- the hobbyists- NOT to go crazy and try to intervene too much. We need to exercise restraint- to let the natural processes which power our aquariums arise, assemble, and thrive.

Hands off! 

That's my continuing challenge to our community..

Yeah, we have to let stuff go a bit. It's really hard for a lot of hobbyists to do this. We're essentially trained from the beginnings of our aquarium experience to scrub, polish, and siphon out everything which doesn't meet some definition of "acceptable."

We've been told that algae growth or fungal growths on our wood or substrate are bad, and must be removed. We've been encouraged to siphon out any decomposing materials, and that stuff like detritus is the source of untold disaster if we let it accumulate in our tanks.

It's hard to make this mental shift. I know. I've been trying to convince people to take this path for the better part of the past decade, and it's finally catching on. Skeptics and haters abound- more than ever, now, as these ideas have gained traction in the aquarium hobby.

It's 100% counterintuitive to everything we've been indoctrinated to believe. And worse, we're asking you to have faith that "stuff will work out" in your tank when you see all of this biofilm and fungal growth, turbid water, decomposition, and perhaps even algae. Stuff that the so-called "Nature Aquairum" crowd would absolutely shit their pants over. 

Well, this IS Nature, boys and girls. 

This is Planet Earth.

And yeah, you're actually not 100% in control. It's not the sanitized, organized, highly stylized "Nature" of your fantasies. It's the "Nature" that's perfectly imperfect, filled with non-ratioed, seemingly disorganized aggregations of materials, and life forms covering everything. You have to cede some of the work in your tank to Nature. You'll "go through some things." Some of the stuff you'll see will be "ugly" to you.

Or, will it be?

Will you perhaps study some of the wild aquatic habitats of the world where our fishes come from, see what makes them function the way that they do- and draw a parallel between what you're seeing in your tank, and what you're seeing in Nature?


Will you hang on?

Will you "wait out" what appears to be an endless explosion of gooey stringy stuff coming out of your leaves, wood, and  and botanicals, and allow your tank to achieve it's own form of equilibrium? Or, will you reach for the siphon hose and pull it all out, disrupting some of Natures's most elegant, valuable, and efficient processes in order to "re-set" and achieve some sort of "instant gratification" that you were told that a spotless, sterile-looking tank will provide?

Yeah. Re-setting the whole thing.

Doing things the way we've done them in then hobby for decades because they give you the predictable results in a short amount of time...

Or, will you see the real beauty of unedited Nature in your very own tank? And the amazing way Nature works it out...If you let Her.


That's the adventure- the challenge of the botanical-style aquarium. A methodology filled with inexact, unconventional, yet well-known natural processes. A methodology which asks you to make some leaps of faith, some educated guesses, and to play some hunches. An evolving, not entirely predictable path to a dynamic, truly remarkable aquarium.

You can do this. You might fail, but you'll likely succeed, especially if you put your faith in Nature.

Be strong. Be patient. Be experimental.

Hang on through the weird, uncomfortable, uncertain, unknown stuff. It's worth it. 

Stay bold. Stay open minded. Stay curious. Stay the course...

And Stay Wet.


Scott Fellman

Tannin Aquatics 








Behind the dynamics of the "Urban Igapo"

I've always been fascinated by environments which transform from dry, terrestrial ones to lush aquatic ones during the course of the year. I remember as a kid visiting a little depression in a field near my home , which, every spring, with the rains would turn into a little pond, complete with frogs, Fairy Shrimp, and other life forms. I used to love exploring it, and was utterly transfixed by the unique and dynamic seasonal transition.

The thrill and fascination of seeing that little depression in the ground, which I later learned was called a "vernal" or "temporal" pool by ecologists, never quite left me. As a fish geek, I knew that one day I'd be able to incorporate what I had seen into my fish keeping hobby...somehow.

About 5 years ago, I got a real "bug up my ass", as they say, about the flooded forests of South America. There is something alluring to me about the way these habitats transition between terrestrial and aquatic at certain times of the year. The migration of fishes and the emergence of aquatic life forms in a formerly terrestrial environment fascinates me- as does the tenacity of the terrestrial organisms which hang on during these periods of inundation. 

So, I began playing with aquariums configured to replicate the function and form of these unique habitats. I spent a lot of time studying the components of the Igapo and Varzea environments- the soils, plants, fauna, etc., and learning the influences which lead to their creation and function.  

Once I had a grasp of the way these dynamic ecologies work, the task of attempting to recreate them in the aquarium became more realistic and achievable. I realized that, although hobbyists have created what they call "Igapo" simulations in biotope contests for years, for example, it was always a representation of the "wet" season.  Essentially a living "diorama" of sorts. Not really a true simulation of the seasonal dynamics which create these habitats.

They were cool, but something was somehow missing to me. With those representations, you throw in some leaves, twigs, and seed pods, maybe a few plants, and call your tank a "flooded forest."  I mean, essentially a botanical-style aquairum, although the emphasis was on appearance, not function. That wasn't really that difficult to do, nor much of a advancement in the current state of the art of aquarium keeping. I could do that already. Rather, I wanted to recreate the process- all of it- or as much as possible- in my aquariums.

Thus, the idea of the "Urban Igapo"- a functional representation of a transitional aquatic habitat was born. 

The concept behind the "Urban Igapo" is pretty straightforward:

The idea is to replicate to a certain extent, the seasonal inundation of the forests and grasslands of of Amazonia by starting the tank in a 'terrestrial phase", then slowly inundating it with water over a period of weeks or more; then, running the system in an "aquatic phase" for the duration of the 'wet season", then repeating the process again and again.  


Because you can do this in the comfort of your own home, we called the concept the "Urban Igapo." About 2 years ago, we went more in depth with some of the procedures and techniques that you'd want to incorporate into your own executions of the idea.


As with so many things in the modern aquarium hobby, there is occasionally some confusion and even misunderstandings about why the hell we do this in the first place! 

Well, that's a good question! I mean, the whole idea of this particular approach is to replicate as faithfully as possible the seasonal wet/dry cycles which occur in these habitats. It starts with a dry or terrestrial environment, managed as such for an extended period of time, which is gradually flooded to simulate inundation which occurs when the rainy season commences and swollen rivers and streams overflow into the forest or grassland.

Sure, you can replicate the "wet season" only- absolutely. I've seen tons of tanks created by hobbyists to do this. However, if you want to replicate the seasonal cycle- the real magic of this approach- you'll find as I did that it's more fun to do the "dry season!"

Think of it in the context of what the aquatic environment is- a forest floor or grassland which has been flooded. If you develop the "hardscape" (gulp) for your tank with that it mind, it starts making more sense. What do you find on a forest floor or grassland habitat? Soil, leaf litter, twigs, seed pods, branches, grasses, and plants.

 Just add water, right?

Well, sort of.

Now, recently, one of my friends who was presenting his experiences with this approach was just getting pounded on a forum by some, well- let's nicely call them "skeptics"- you know, the typical internet-brave "armchair expert" types- about why you'd do this and how it can't lead to a stable aquarium and how it's "not a blackwater aquarium" (okay, it wasn't presented as such, but it could be...) and that it's just a "dry start" (Well, sort of, but you have to understand the concept behind it, dude), and that you don't need to do it this way and...well- that kind of stuff.

I mean, the full compliment of negative, ignorant, questions by people clearly frightened about someone trying to do something a little differently. In a typical display of online-warrior hypocrisy, one particularly nasty hack did not even bother to research the idea or think about what it was really trying to do before laying into my friend.

Apparently, for these people, there was a lot to unpack.

I mean, first of all, the idea was not intended to be a "dry start" planted tank. It just wasn't. I mean, it starts out "dry", but that's where the similarity ends. This ignorant comment is a classic example of the way some hobbyists make assumptions based on a superficial understanding of something.

We aren't trying to grow aquatic plants here. It's about creating a habitat of terrestrial plants snd grasses, allowing them to establish, snd then inundating the display. Most of the terrestrial grasses will simply not survive extended periods of time submerged. Now, you COULD add adaptable aquatic plants- there are no "rules"- but the intention was to replicate a seasonal dynamic. 

The other point, which is utterly lost on some people, is that establishing a "transitional" environment in an aquarium takes time and patience. One dummy literally called the process "complete nonsense" and a "waste of time." This is exactly the kind of self-righteous, ignorant hobbyist who will never get it. In fact, I'm surprised guys like that actually have any success at anything in the hobby.

Such a dismissive and judgmental attitude. 

So, once again, let's contemplate what happens in Nature in the "rainy season" in say, the Amazon Basin.


The wet season in The Amazon runs from November to June. And it rains almost every day. And what's really interesting is that the surrounding Amazon rain forest is estimated by some scientists to create as much as 50% of its own precipitation! Think about THAT for a minute. It does this via the humidity present in the forest itself, from the water vapor present on plant leaves- which contributes to the formation of rain clouds.

Yeah, trees in the Amazon release enough moisture through photosynthesis to create low-level clouds and literally generate rain, according to a recent study published in the Proceedings of the National Academy of Sciences (U.S.)!

That's crazy.

But it makes a lot of sense, right?

Yet another reason why we need to protect these precious habitats. You cut down a tree in the Amazon- you're literally reducing the amount of rain that can be produced.

It's that simple.

That's really important. It's more than just a cool "cocktail party sound bite."

So what happens to the (aquatic) environment in which our fishes live in when it rains? What does the rain actually do?

Well, for one thing, rain performs the dual function of diluting organics, while transporting more nutrient and materials across the ecosystem. What happens in many of the regions of Amazonia, for example- is the evolution of our most compelling environmental niches. The water levels in the rivers rise significantly. often several meters, and the once dry forest floor fills with water from the torrential rain and overflowing rivers and streams.

The Igapos are formed. 

Flooded forest floors.

The formerly terrestrial environment is now transformed into an earthy, twisted, incredibly rich aquatic habitat, which fishes have evolved over eons to live in and utilize for food, protection, and spawning areas.

All of the botanical material-shrubs, grasses, fallen leaves, branches, seed pods, and such, is suddenly submerged; often, currents re-distribute the leaves and seed pods and branches into little pockets and "stands", affecting the (now underwater) "topography" of the landscape.

Leaves begin to accumulate.

Soils dissolve their chemical constituents- tannins, and humic acids- into the water, enriching it. Fungi and micororganisms begin to feed on and break down the materials. Biofilms form, crustaceans multiply rapidly.  Fishes are able to find new food sources; new hiding areas to spawn.

Life flourishes.

So, yeah, the rains have a huge impact on tropical aquatic ecosystems. And it's important to think of the relationship between the terrestrial habitat and the aquatic one when visualizing the possibilities of replicating nature in your aquarium in this context.

It's an intimate, interrelated, "codependent" sort of arrangement!

To replicate this process is really not difficult. The challenging part is to separate what we are trying to do here from our preconceptions about how an aquarium should work. To understand that the resulting aquatic display won't initially look or function like anything that we're already familiar with.

While it superficially resembles the "dry start" method that many aquatic plant enthusiasts play with, it's important to remember that our goal isn't to start plants for a traditional aquarium. It's to establish terrestrial growth and to facilitate a microbiome of organisms which help create this habitat. It's to replicate, on some levels, the year-round dynamic of the Amazonian forests. We favor terrestrial plants- and grasses-grown from seed, to start the "cycle."

So, those of you who are ready to downplay the significance of experimenting with this stuff because "people have done 'dry start' planted tanks for years", take comfort in the fact that I recognize that, and acknowledge that we're taking a slightly different approach here, okay?


You'll need to create a technical means or set of procedures to gradually flood your "rainforest floor" in your tank, which could be accomplished manually, by simply pouring water into the vivarium over a series of days; or automatically, with solenoids controlling valves from a reservoir beneath the setup, or perhaps employing the "rain heads" that frog and herp people use in their systems. This is all very achievable, even for hobbyists like me with limited "DIY" skills.

You just have to innovate, and be willing to do a little busy work. You can keep it incredibly simple, and just utilize a small tank.

You must be patient.

And of course, there are questions. Here are some of the major/common ones we receive about this concept:

Does the grass and plants that you've grown in the "dry season" survive the inundation?

A great question. Some do, some don't. (How's that for concise info!). I've played with grasses which are immersion tolerant, such as Paspalum. This stuff will "hang around" for a while while submerged for about a month and a half to two months, in my experience, before ultimately succumbing. Sometimes it comes back when the "dry season" returns. However, when it doesn't survive, it decomposes in the now aquatic substrate, and adds to the biological diversity by cultivating fungi and bacteria.

You can use many plants which are riparian in nature or capable of growing emmersed, such as my fave, Acorus, as well as all sorts of plants, even aquatics, like Hydrocotyle, Cryptocoryne, and others. These can, of course, survive the transition between aquatic and "terrestrial" environments.

How long does the "dry season" have to last?

Well, if you want to mimic one of these habitats in the most realistic manner possible, follow the exact wet and dry seasons as you'd encounter in the locale you're inspired by. Alternatively, I'd at least go 2 months "dry" to encourage a nice growth of grasses and plants prior to inundation.

And of course, you cans do this over and over again! If you're trying to keep fishes like annual killifishes, the "dry season" could be used on the incubation period of their eggs.

When you flood the tank, doesn't  it make a cloudy mess? Does the water quality decline rapidly? 

Sure, when you add water to what is essentially a terrestrial "planter box", you're going to get cloudiness, from the sediments and other materials present in the substrate. You will have clumps of grasses or other botanical materials likely floating around for a while.

Surprisingly, in my experience, the water quality stays remarkably good for aquatic life. Now, I'm not saying that it's all pristine and crystal clear; however, if you let things settle out a bit before adding fishes, the water clears up and a surprising amount of life (various microorganisms like Paramecium, bacteria, etc.) emerges.

Curiously, I personally have NOT recorded ammonia or nitrite spikes following the inundation. That being said, you can and should test your water before adding fishes. You can also dose bacterial inoculants, like our own "Culture" or others, into the water to help. The Purple Non-Sulphur bacteria in "Culture" are extremophiles, particularly well adapted to the dynamics of the wet/dry environment.

Should I use a filter in the "wet season?"

You certainly can. I've gone both ways, using a small internal filter or sponge filter  in some instances. I've also played with simply using an air stone. Most of the time, I don't use any filtration. I just conduct partial water exchanges like I would with any other tank- although I take care not to disturb the substrate too much if I can. When I scaled up my "Urban Igapo" experiments to larger tanks (greater than 10 gallons), Il incorporated a filters with no issues. 

A lot of what we do is simply letting Nature "take Her course." 

Ceding a lot of the control to Nature is hard for some to quantify as a "technique" or "method", so I get it. At various phases in the process, our "best practice" might be to simply observe...

And with plant growth slowing down, or even going completely dormant while submerged, the utilization of nutrients via their growth diminishes, and aquatic life forms (biofilms, algae, aquatic plants, and various bacteria, microorganisms, and microcrustaceans) take over. There is obviously an initial "lag time" when this transitional phase occurs- a time when there is the greatest opportunity for one life form or another (algae, bacterial biofilms, etc.) to become the dominant "player" in the microcosm.

It's exactly what happens in Nature during this period, right?

And there are parallels in the management of aquariums.

In our aquarium practice, it's the time when you think about the impact of technique-such as water exchanges, addition of aquatic plants, adding fishes, reducing light intensity and photoperiod, etc. and (again) observation to keep things in balance- at least as much as possible. You'll question yourself...and wonder if you should intervene- and how..

It's about a number of measured moves, any of which could have significant impact- even "take over" the system- if allowed to do so. This is part of the reason why we don't currently recommend playing with the Urban Igapo idea on a large-tank scale just yet. (that, and the fact that we're not going to be geared up to produce thousands of pounds of the various substrates just yet! 😆)

Until you make those mental shifts to accept all of this stuff in one of these small tanks, the idea of replicating this in 40-50, or 100 gallons is something that you may want to hold off on for just a bit.

Or not.

I mean, if you understand and accept the processes, functions, and aesthetics of this stuff, maybe you wouldwant to "go big" on your first attempt. However, I think you need to try it on a "nano scale" first, to really "acclimate" to the idea.

The idea of accepting Nature as it is makes you extremely humble, because there is a realization at some point that you're more of an "interested observer" than an "active participant." It's a dance. One which we may only have so much control- or even understanding of! That's part of the charm, IMHO.

These habitats are a remarkable "mix" of terrestrial and aquatic elements, processes, and cycles. There is a lot going on. It's not just, "Okay, the water is here- now it's a stream!"

Nope. There is a lot of stuff to consider.

In fact, one of the arguments one could make about these "Urban Igapo" systems is that you may not want to aggressively intervene during the transition, because there is so much going on! Rather, you may simply want toobserve and study the processes and results which occur during this phase. Personally, I've noticed that the "wet season" changes in my UI tanks generally happen slowly, but you will definitely notice them as they occur. 

After you've run through two or three complete "seasonal transition cycles" in your "Urban Igapo", you'll either hate the shit out of the idea- or you'll fall completely in love with it, and want to do more and more work in this alluring little sub-sector of the botanical-style aquarium world.

The opportunity to learn more about the unique nuances which occur during the transition from a terrestrial to an aquatic habitat is irresistible to me. Of course, I'm willing to accept all of the stuff with a very open mind. Typically, it results in a fascinating, utterly beautiful, and surprisingly realistic representation of what happens in Nature.

It's also entirely possible to have your "Urban Igapo" turn into an "Urban Algae Farm" if things get out of balance. Yet, it can "recover" from this. Again, even the fact that a system is "out of balance" doesn't mean that it's a failure. After all, the algae is thriving, right? That's a success. Life forms have adapted. A cause to celebrate.

It happens in Nature, too!

So, that's a brief rundown on the dynamics and challenges of the "Urban Igapo" concept. It will be exciting to see how each of us evolves the idea further!

Stay creative. Stay thoughtful. Stay bold. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics  

The game of change...

As human beings, thankfully, each one of us is different. As hobbyists, this is especially true, and completely evident when one considers the wide variety of approaches we take to creating and managing our aquariums.

And, fish geeks being fish geeks, we all have our little idiosyncrasies and quirks. I know that I have some that get to me.

Like, a desire to make radical changes, seemingly out of the blue. Now, sure, I am the guy who gives a lot of his tanks and ideas plenty of time and space to "breathe" and develop over time. I'm pretty patient when it come to letting my tanks evolve. 

However, I admit- I DO like to change stuff up sometimes.

Ever wake up one morning just..hits you? That urge to change up your aquarium; it's look, "theme"- whatever?


I don't think that it's just a "me" thing, either.

It's part of being a fish geek, I think. 

We look at our existing aquarium and say, "I really love it, but...."

We reach for some towels, grab a bucket, and it's on!

I think it's part of the mental makeup- the fabric, if you will- of the fish geek.

We're sort of almost "programmed" to want to switch stuff up after a while, right? It's like we want to create, modify, renew...or just try something different. 

For many hobbyists, their one aquarium is the only one they can have- at least for now, but possibly forever. Space, economics, time, etc, all come into play, and there really isn't much you can do except work with the one you've got. I mean, it's a blessing to have even one...but to the serious fish geek, that desire to move on to a greener pasture (or should we say, "bluer river?")-to just taste some new stuff- seldom retreats.

I've been resigned at home to some small, temporary tanks until I complete a major remodeling project, and it's been a real test of my patience working with these makeshift systems until I can once again set up my larger, permanent tanks. And I find that they don't seem to hold my interest as long as the larger tanks do.

Can you relate?  

I think- think- that it's often augmented by my desire as the Tannin "mothership" and a need to continuously showcase new ideas and botanicals. Well, maybe that's an excuse.

But hey, we all love to try new stuff, right?

I know that I do.

And it's funny, because I think that even though I fancy myself as this restless "conceptual" guy who is constantly evolving his ideas, the reality is that my "makeovers" are seldom that radical- rather, their little iterations that represent incremental changes or improvements over previous designs.

I tend to "stay in my lane", and not stray all that far from it.

I almost envy those of you who can make radical changes at the spur of the moment without regret or a whole lot of consideration.

I often wonder why I play with such a tight set of characteristics- you know, certain wood arrangements, use of specific textures, colors, etc. Although I'm definitely prone to "over-analyzing" stuff at times, it's fun now and then to step out of my own mind and look at stuff as if I'm a "third party" of sorts.

Maybe I have that sort of "comfort zone" that I tend not to push myself out too far from. I mean, I operate in a pretty radical "sector" already- the blackwater, botanical-style world. It's not everyone's cup of tea, being pretty different from the conventional, "clear water" aquariums we all know so well. I realized a long term ago that, when I make changes to my tanks, they're almost always more like "iterations" of the existing concept.


Yeah, the "next steps" are often subtle in nature. 

And I think that it's sort of "baked into" the idea of botanical-style aquariums: We set the stage for what nature does. Rather than trying to create a "finished product", I think those who operate in our arena tend to set the stage and let Nature do the rest of the work over time. 

Interestingly, you can still make seemingly dramatic changes to your aquariums, and yet leave considerable parts of them intact and functional. This works great with botanical-style aquariums.

Nature does this all the time.

The idea of leaving the substrate and leaf litter/botanical "bed" intact as you "remodel" isn't exactly a crazy one. And conceptually, it's sort of replicates what occurs in Nature! Materials accumulate on top of other materials, facilitating new biological growth, continued foraging for resident fishes, and a more or less uninterrupted ecology.

Yeah, think about this for just a second.

As we almost constantly discuss, habitats like flooded forests (Igapo and Varzea), meadows, vernal pools, igarape, and swollen streams, which tend to encompass terrestrial habitats, or go through phases where they are terrestrial habitats- for a good part of the year.

In these wild habitats, the leaves, branches, soils, and other botanical materials remain in place, or are added to by dynamic, seasonal processes. For the most part, the soil, branches, and a fair amount of the more "durable" seed pods and such remain present during both phases.

The biggest "disruption" in these habitats is often the transformation from terrestrial to aquatic. However, the "hardscape" (to borrow an aquarium term) largely remains intact.

Sure, a "makeover" of an aquarium can be a seriously disruptive event (for both YOU and your fishes!).

On the other hand, if you take the mindset that this is a "transformation" of sorts, and act accordingly, it becomes more of an evolutionary process. This is something I've done for many years- like a lot of you have, and it not only makes your life a bit easier- it can create pretty good outcomes for the fishes we keep.

The "Urban Igapo" idea that I've been touting for a good part of the past 3 years is a very deliberate execution of this "iterative process", and it's taught me quite a bit about how these habitats function in Nature, and what kinds of benefits they bring to the aquarium.

We've talked about the idea of "flooding" an aquarium setup designed to replicate an Amazonian forest before. You know, sort of attempting to simulate some of the processes which happen seasonally in Nature. With the technology, materials, and information available to us today, the capability of creating a true "year-round" habitat simulation in the confines of an aquarium/vivarium setup has never been more attainable.

These are deliberate, more transformative executions by design.

However, making changes to every existing aquarium does not need to be a super-complicated, highly disruptive thing, right? I’m not advocating 360-degree changes in your aquarium management approach every time something doesn’t give you desired results in 3 days, or every time you're "not feeling it." That's a recipe for chaos

What I am thinking about here is developing the "mental ability" to get yourself easily out of a situation that is simply not working for you- for the benefit of your animals, budget, time- and sanity. Shit, it’s a hobby, so if you’re not enjoying it, what’s the point?

So, maybe it’s not “move fast and break things” for you…perhaps it’s “move at a nice rate of speed and change moderately quickly when things don’t work out.”

What are the benefits of adopting a “move fast” philosophy- or at least the gist of it- for you as an aquarist?

First, you can test a lot of ideas and concepts on your tank relatively quickly, in “real time”, rather than just reading about them on the forums. If you have a general idea of where you want to go with your tank, but are interested in a few approaches, this is not a bad way to go.

You can work in multiple ideas to see if they work, and throw out the ones that don’t, relatively quickly. Now, again, I’m not talking about major hardware shuffles (“Yeah, the 350 was too small, so three weeks later, I broke it down and ordered a 700.” That’s pure insanity). Nope, I’m talking about “tweaks”, like deciding to feed your predatory fishes only at night- or a few days a week…or, perhaps dosing fertilizers only when the display is dark. Changing flow patterns, feeding times, light combinations. "Pulsing" leaf additions...Tweaking.

Not full-scale, drain-the-tank-and-start-from-scratch overhauls. 

Second, you can certainly learn stuff at a more rapid clip, right? If you’re giving yourself the opportunity to “audition” a practice, philosophy, procedure, etc., you can find out if something makes sense a whole lot more than if you commit 1,000 percent to a rigid philosophy of “I’m only going to do it this way.” 

Even if you don’t get the "whole picture" of what’s happening in your tank, attempting quick little experiments can give you an indication of the general direction or trend- an answer to a little piece of the puzzle that you can incorporate to evolve more successfully in the long term.

Finally, this philosophy actually can force you to look at things more "honestly."

In other words, if you decided to do something that maybe you thought might not work- by committing yourself to a “nothing is sacred” attitude at the start of your project, you can evaluate things in a more direct manner, and change things up as necessary to assure overall success of the tank and the health of its inhabitants. If you throw the “fun” part back into the equation, and share your trials and tribulations with other hobbyists, it certainly makes it more enjoyable to stop being stubborn and try to make things work, right? 

Of course, for every action, there’s an equal and opposite reaction, right? So, what are the downsides to a rapid-iteration, “move fast and break things” philosophy?

To  begin with, you will probably build some “mental debt.” In other words, as you rapidly make changes and move things along, you may tend to overlook other things. Human nature, right? You tend to look at every change or iteration as a big experiment, and that you can “fix stuff later”- a kind of dangerous trap to fall into, especially when you think of the potential impact on living organisms.

It’s one thing to make intelligent, measured changes, but to take shortcuts, non-sustainable work-arounds, and “band aids” harbors potential hidden dangers. Be alert to this. Your “pursuit of perfection” could result, ironically, in you never quite getting it right?

In addition, you might find yourself “burnt out” rather quickly. I mean, if you’re chaotically trying every new idea, every new gadget that’s out there in trying to find quick solutions, you will not likely enjoy this hobby for very long. It’s a marathon, not a sprint, right? I mean, it’s a “hobby” at the end of the day. Yet, each day I read forum posts from dozens of hobbyists who flail helplessly in multiple directions, trying every little thing to "change-up" their tank, in a desperate attempt to solve a relatively simple problem.

Algae issues are notorious for soliciting this kind of behavior- the desire to get the problem “solved” has resulted in many disasters (like using all sorts of chemicals and medications to eradicate algae, when the reality is that it could have been eradicated or managed with husbandry tweaks to begin with…). Some of these "fixes" result in a destroyed biome and dead fishes.

Think before you forge ahead with potentially long-term detrimental "fixes."

So, in summary. Changing stuff up- even relatively rapidly- isn't a bad thing, if it's done for the right reasons. Maybe it's "Aquatic A.D.D." or something (I have this theory, lol), but I think it can actually be a good thing. I even think I understand why some people change up their tanks so often.

With me, I suppose I could rationalize occasional bouts of this "fast change syndrome" by telling myself that it's a matter of wanting to try a lot of concepts out which get's me moving. The desire to move into different directions, despite having limited resources of space, time, or money.


Better to let the full range of your imagination inspire and guide you, instead of limit you. That's why I treasure thinking outside the box so much. Not because it's cool to just do things differently "because." Rather, it's because it's really important to follow up on some of those thoughts and ideas we have. Every single one has the potential to lead to some breakthrough or advancement in the hobby.

Use the relentless flow of ideas- and your ability to execute and accept change- to your advantage.

Every single one has potential.

Don't downplay those ideas that pop into your head from time to time, even if it means changing some stuff up. And they don't always have to be super well thought-out ideas, either. 

Sometimes, you can play a "hunch", a "feeling", or a "whim"-and come up with something great.

Can't you think of at least a few things that you tried on a whim, only to realize later that they were incredible efforts that brought you so much joy?

I'll bet that you can.

Execute each one in it's own time. Let them breathe. Develop them. Or squash them quickly. 

But do try them.

Because it's far better to do something than to just think about it, IMHO.

Consistency is important. 

However, change can be good. Really good.

Stay dedicated. Stay focused. Stay reflective. Stay happy...

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:

" 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 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'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 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 the right way.

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

And Stay Wet.


Scott Fellman
Tannin Aquatics