June 24, 2019


Philosophy, tint, and transience...

With our aquarium work, we marry art, science, and, yeah- philosophy. An important mix, really.

In its most simplistic and literal form, the Japanese philosophy of "Wabi Sabi" is an acceptance and contemplation of the imperfection, constant flux and impermanence of all things.

This philosophy was been embraced in aquascaping circles by none other than the late, great, Takashi Amano, who proffered that a planted aquarium aquascape is in constant flux, and that one needs to contemplate, embrace, and enjoy the sweet sadness of the transience of life.

This is a fascinating and meaningful philosophy, IMHO.

Many of Amano's greatest works embraced this philosophy, and evolved over time as various plants would emerge, thrive, spread and decline, re-working and reconfiguring the aquascape with minimal human intervention. Each phase of the aquascape's existence brought new beauty and joy to those would observe them.

This philosophy of "meeting Nature where it is" is the perfect encapsulation of what happens in an aquarium..specifically, the botanical-style systems we love. If someone pressed me to name the single most important thing you need to understand and embrace to be successful when working in this arena, this concept would be it.

Yet, in today's "contest-scape-driven", "break-down-the-tank-after the show" world, this philosophy of appreciating change by nature over time seems to have been tossed aside as we move on to the next 'scape. Emphasis has been placed on the production of a "product" or "finished work" in a relatively short period of time, versus allowing something to evolve. And yeah, the three-month "pre contest period" before you take pics and submit is NOT allowing your tank to evolve. It's just a start. 

It goes for any tank, IMHO. These things take time. Patience. Observation. Appreciation. Changes caused by Nature are often subtle, maybe barely perceptible- but they're happening. We need to train ourselves to be attuned to them.

When we use natural botanical materials in our aquatic hardscape, such as leaves and softer botanicals, which begin to degrade after a few weeks submerged, one can really understand the practicalities of this philosophy. It could be argued, that the use of botanicals in an aquarium and embracing the progression is the very essence of what "Wabi Sabi" is about.

I love that the mainstream aquarium wold is looking at this stuff more seriously. However, with hobbyists worldwide getting interested in blackwater, botanical-style tanks, and more and more aquatics vendors starting to offer "botanicals" sections on their web sites, I think that we have to ask ourselves, "Why are we doing this?

Is it because this is suddenly "cool?" Because it's a way to have a "hip and trendy-looking" tank? Is it because somebody told us to do it? Or is it perhaps something else?

Are we as a hobby understanding that this type of tank goes way, way beyond the "typical" purely aesthetic-driven scapes that have been "the thing" for the last couple of decades? The "functional aesthetic" concept that we embrace here is really the cornerstone of this "movement" in the hobby.

It starts with the way we "configure" our aquascapes. How we "set them up" to follow Nature's course, rather than fight it.

I've always personally felt that, in a botanical-style aquarium, a hardscape should have some more-or-less "permanent" materials, like driftwood, complemented by some of the more durable botanicals, like Cariniana pods or Sterculia pods, and enhanced by more "degradable" items, like as the "softer" seed pods and such, and finally, complimented by the use of leaves- which are perhaps the most "ephemeral" component of the botanical-style aquarium, and need replenishment/replacement over time.

As we know, natural botanical materials not only offer very unique natural aesthetics- they offer literal "enrichment" of the aquatic habitat through their release of tannins, humic acids, vitamins, etc. as they decompose- just as they do in nature.

This is a pretty amazing thing.

Much like flowers in a garden, leaves will have a period of time where they are in all their glory, followed by the gradual, inevitable encroachment of biological decay. At this phase, you may opt to leave them in the aquarium to enrich the environment further (providing food for fungi, bacteria, and other fauna), and offer a different aesthetic, or you can remove and replace them with fresh leaves and botanicals.

This very much replicates the process which occur in nature, doesn't it?

With the publishing of photos and videos of leave-influenced 'scapes in the past few years, there has been much interest and more questions by hobbyists who have not really considered these items in an aquascape before. This is really cool, because new people with new ideas and approaches are actively experimenting.  And, perhaps most important of all- we're looking at nature as never before. We're celebrating the real diversity and appearance of natural habitats as they really are...

Some hobbyists have commented that, as their leaves and botanicals break down and the scape as initially presented changes significantly over time. Weather they know it or not, they are grasping "Wabi-Sabi"...Well, sort of. One must appreciate the beauty at various phases to really grasp the concept and appreciate it. To find little vignettes- little moments- of fleeting beauty that need not be permanent to enjoy.

And of course, there are always some people who just "don't get it", and proffer that this is simply sloppy, not thought-out, and seemingly random approach to aquarium keeping. I recall vividly one critic on a Facebook forum, who, observing a botanical-inspired aquascape created by another hobbyist, commented that the 'scape looked like "...someone just threw in some pods and leaves in a random fashion.." 

Yeah, this guy actually did superficially describe the aesthetic to a certain (although very unsophisticated) degree...but he couldn't get past the superficial assessment of the look, which was in conflict with his personal taste, and therefore concluded it was, "...haphazard, sloppy, and not thought out."

Had he ever actually been to, or seen pictures of, a natural aquatic habitat? I couldn't help but wonder. The lack of ability to get out of this head space that "natural" = sloppy, poorly thought out, and unsophisticated.


But on the other hand, that sort of random, almost "deconstructed" look was the charm and beauty of the tank in question. The seemingly transient nature of such an aquascape, with leaves deposited as in nature by currents, tidal flows, etc., settling in unlikely areas within the hardscape is beautiful.

Not everyone likes this nor appreciates it. Or understands it. And that's perfectly fine. Not everyone finds brown water, decomposing leaves, biofilms, and detritus beautiful. A lot of aquarists just sort of shrug. Some even laugh. Some love to criticize.

It's not the "best" way to run a tank. Just "a way."

Some want "rules." Order. Guidelines from experts.

We offer no "rules."

We can only offer an assessment of what Nature does to an aquarium when it's set up a certain way. We can only point out the way Nature looks and study how it functions, and perhaps offer some hints on how to embrace the processes which it utilizes.

There are no real "rules" when creating a blackwater/botanical-style aquarium, other than the biological aspects of decomposition and water chemistry, which are the real factors that dictate just how your aquascape will ultimately evolve.

Accepting this inevitable change and imperfection is the very essence- and beauty- of the "Wabi-Sabi" principle, IMHO.

It's about observation. Dedication. Imagination. Individuality. And the mindset of meeting Nature where it is.

Stay contemplative. Stay observant. Stay curious. Stay inquisitive. Stay patient.  Stay unique...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

June 23, 2019


Putting the "botanical puzzle" together...

It's been an interesting journey in the first four years of our existence here at Tannin. With your support and enthusiasm, we've recruited a global community of natural-style botanical aquarium enthusiasts who are pushing the boundaries of the science and art of aquarium keeping.

We've started with some simple ideas, inspired by Nature, and have slowly refined our skills as a community, moving on towards more and more complex and boundary-pushing ideas. Once tentative about using seed pods, leaves, and twigs to influence the environmental parameters of our tanks, we're now using them to more realistically recreate natural habitats than ever before.

Confidence is high, boosted by experience and success- and replicable results.

It's like we're slowly but surely accumulating the experience and knowledge to put various pieces of this compelling puzzle together- and hopefully, having lot of fun and inspiring others as we do so! 

Inspiration and fun are the keys. Education and experience are the lovely by-products of our efforts as a community.

As a group, we're elevating the use of natural materials- not just to create an aesthetic- but to foster natural behaviors in our fishes and function in our aquariums. These aspects have driven many of us to look at Nature as a source of true inspiration for many aspects of this work.

We're "editing" previously long-held assumptions and ways of doing things to evolve our practices to be much more like what Nature is, as opposed to simply replicating the look of last year's aquascaping contest winner.

And the results are both functional and attractive! And educational, as well!

And there are as many questions as answers. Among the most common? They're about plants.

Specifically, how to use them in our specialized aquariums. 

We get a lot of questions about the types of plants that exist in the igapo (blackwater flooded forest) and varzea ("white-water" flooded forest) habitats that we obsess over so much- what species would work in our aquariums, etc. The interesting thing is that a high percentage of species which occur in this habitat are NOT true aquatics:

"Among the 388 herbaceous species identified in the floodplain areas of Rio Amazonas 330 species (85%) were classified as terrestrial plants, 34 (9%) aquatic plants and the 22 remaining (6%) as intermediary species." (Junk and Piedade, 1993a)

So, yeah, if you want to truly replicate the igapo, you're going to have to utilize some terrestrial plants- mainly grasses, which form dominant, monospecific stands,  such as Echinochloa polystachya, Paspalum fasciculatum, and Paspalum repens.

Now, these are the exact species...one could find representative species from these genera available as seeds. And, you could plant them, and...well. It takes a LOT of patience and time...

Oh, and there are true aquatic plants which are found in some of these flooded igapo habitats. Species which we might have some hobby familiarity with. In fact, common species found at the igapós of rio Negro are: Oryza perennis,  Nymphaea rudgeana, Polygonum sp., Utricularia foliosa, and- wait for it...our old friend, Cabomba aquatica!

Yeah, so there are true aquatic plants in some of these habitats, although the bulk of what we see in many of those breathtaking underwater shots are terrestrial grasses and shrubs which can withstand inundation. Think on that just a bit.

Much still to learn and practice and perfect as we solve this great "puzzle!"

I kind of like where we're going in our botanical aquarium habitat-replication journey, and where we've already been. So far, we've "proof- of-concepted" a 100% leaf-litter habitat with tremendous success. It works fantastically, is a completely different aesthetic than anything we've done before, and has enormous potential.

We've also played with the idea of replicating a tangle of roots, as one sees in the igapo and varies habitats. The web of life that exists in this habitat is awe-inspiring!

This has also proven to be an amazing "look" and has a functional aspect to it that we're still working with. My (now 6 month old) "Tucano Tangle" featuring roots and the enigmatic Tucanoichthys tucano is still teaching me new lessons on the "functional aesthetic" aspect of this habitat in the aquarium. 

Next, it's on to incorporating all that we've played with...Leaves, wood, sediments, roots, and immersion-tolerant terrestrial plants. 

Much to be learned. Much to be inspired by. 

Keep looking to Nature for inspiration. I know that I am!

Stay unique. Stay challenged. Stay bold. Stay observant. Stay resourceful...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

June 21, 2019


Cooking with botanicals: The art of botanical preparation- Part 236...

Why do we boil stuff that we add to our aquariums in the first place?

Yeah, it's THE single most common question that we're asked here at Tannin, and has been the starting point for I-don't-know-how-many discussions over the years! So, let's touch on it again! 

Why, Scott? Why do we boil this stuff?

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

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

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

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

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

Then we boil.

Boiling also serves to soften botanicals.

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



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

Are there variations on this theme?

Well, sure.

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

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

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

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

So why do we soak after boiling?

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

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

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

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

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


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

Yeah, those damn things can be a pain! 

However, I think the effort is worthwhile.

Now, sure, I hear tons of arguments which essentially state that "...these are natural materials, and that in Nature, stuff doesn't get boiled and soaked before it falls into a stream or river." Well, damn, how can I argue with that? The only counterargument I have is that these are open systems, with far more water volume and throughput than our tanks, right? Nature might have more efficient, evolved systems to handle some forms of nutrient excesses and even pollution. It's a delicate balance, of course.

In the end, preparation techniques for aquatic botanicals are as much about prevention as they are about "preparation." By taking the time to properly prepare your botanical additions for use in the aquarium, you're doing all that you can to exclude unwanted bacteria and microorganisms, surface pollutants, excess of sugars and other unwelcome compounds, etc. from entering into your aquarium. 

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

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

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

And Stay Wet.


Scott Fellman

Tannin Aquatics



June 20, 2019


"Wood" you believe this?

As an aquarist who derives great pleasure from seeing his fishes "live off the land" and consume foods from the aquarium environment in which they reside, I really find some of the underlying feeding strategies fascinating. One of the best examples is the consumption of wood by various species of fishes.

We read a lot about fishes which eat wood and wood-like materials. Of course, the ones that come immediately to mind are the Loricariidae, specifically, Panaque species. Now, I admittedly am the last guy who should be authoritatively discussing the care of catfishes, but I do understand a little bit about their diets and the idea of utilizing wood- and botanical materials- in the aquarium for the purpose of supplementing their diets!

And of course, I'm fascinated by the world of biofilms, decomposition, microorganism growth and detritus...And this stuff plays right into that! 

Now, the idea of xylophagy (the consumption and digestion of wood) is of course, a pretty cool and interesting adaptation to the environment from which these fishes come from. And as you'd suspect, the way that wood is consumed and digested is equally cool and fascinating! 

It's thought that the scraping teeth and highly angled jaws of the Loricariidae are a perfect adaptation to this feeding habit of scraping wood. And of course, it's even argued among scientists that these fishes may or may not actually digest the wood they consume! While scientists have identified a symbiotic bacteria which is found in the gut of these fishes that helps break down wood components, it's been argued by some the the fishes don't actually digest and metabolize the wood; indeed deriving very little energy from the wood they consume!

In fact, a lab study by Donovan P. German was described in the November, 2009 Journal of Comparative Physiology, in which several species were fed wood and found to actually digest it quite poorly: 

"...in laboratory feeding trials, (P. cf. nigrolineatus and Hypostomus pyrineusi)  lost weight when consuming wood, and passed stained wood through their digestive tracts in less than 4 hours. Furthermore, no selective retention of small particles was observed in either species in any region of the gut. Collectively, these results corroborate digestive enzyme activity profiles and gastrointestinal fermentation levels in the fishes’ GI tracts, suggesting that the wood-eating catfishes are not true xylivores such as beavers and termites, but rather, are detritivores like so many other fishes from the family Loricariidae."

Did you see that? Detritioves.


And this little nugget from the same study:  "...The fishes consumed 2–5% of their body mass (on a wet weight basis) in wood per day, but were not thriving on it, as P. nigrolineatus lost 1.8 ± 0.15% of their body mass over the course of the experiment, and Pt. disjunctivus lost 8.4 ± 0.81% of their body mass."

Yet, anatomical studies of these fishes showed that the "wood-eating catfishes" had what physiologists refer to as "body size-corrected intestinal lengths" that were 35% shorter than the detritivore species. What does this mean? Could they have perhaps had at one time- and subsequently lost- their ability to digest wood?



To the point of the argument that they are primarily detritivores, consuming a matrix of biofilm, algal growth, microorganisms, and (for want of a better word) "dirt"- what does this mean? In fact, many species in the Loricariidae are known to be detritivores, and this has made them remarkably adaptable fishes in the aquarium.

Now, my personal experience with Loricariidae is nothing like many of yours, and an observation I made not too long ago is at best anecdotal- but interesting:

If you follow "The Tint", you know I've had an almost two year love affair with my Peckolotia compta aka "L134 Leopard Frog"- a beautiful little fish that is filled with charms. Well, my specimen seemed to have vanished into the ether following a re-configuration/rescape of my home blackwater/botnanical-style aquarium. I thought somehow I either lost the fish during the escape, or it died and subsequently decayed without my detecting it... 

For almost three months, the fish was M.I.A., just....gone.

And then one, day- there she was, poking out from the "Spider Wood"thicket that forms the basis of my newer hardscape! To say I was overjoyed was a bit of an understatement, of course! And after her re-appearance, she was been out every day. She looked just as fat and happy as when I last saw her in the other 'scape...which begs the question (besides my curiosity about how she evaded detection)- What the @#$% was she feeding on during this time?

Well, I suppose it's possible that some bits of frozen food (I feed frozen almost exclusively) got away from my population of hungry characins and fell to the bottom...However, I'm pretty fastidious- and the other fishes (characins) were voracious! I think it was more likely the biofilm, fungal growth, and perhaps some of the surface tissues of the "Spider Wood" I used in the hardscape that she was feeding on.

This stuff does recruit some biological growth on it's surfaces, and curiously, in this tank, I noticed during the first few months that the wood seemed to never accumulate as much of this stuff as I had seen it do in past tanks which incorporated it.

I attributed this to perhaps some feeding by a population of Nanostomus eques, which have shown repeatedly in the past to feed on the biofilm or "aufwuchs" accumulating on the wood.

And as an interesting side observation, this wood (so-called "Blonde" Spider Wood) actually darkens and develops a sort of "patina" of biofilms and such over time, which probably facilitates the feeding, right?

There was also a layer of Live Oak leaves distributed throughout the booth of the wood matrix, which, although they break down very slowly compared to other leaves we use, DO ultimately soften over time and break down over time.

Interestingly, in this tank, I was finding little tiny amounts of very broken-down leaves, which I attributed to decomposition, but thinking back on it, looks more like the end product of "digestion" by someone!

I must admit, I don't think I've ever seen my L134 consuming prepared food. I've always seen her rasping away at the wood surfaces and on botanicals...That's all the proof I needed to confirm my theory that she's pretty much 100% detritivorous, and that the botanical-style aquariums she's resided in provide a sufficient amount of this material for her to consume.

SO, back the the whole "xylophore thing"...I think that in the aquarium, as well as in the wild, much of what we think is actually "consumption" of the wood is simply incidental, as in, the fishes are trying to eat the biocover and detritus on the surface tissues of the wood, but do a pretty good job (with their specialized mouthparts) of rasping away the surface tissues as well.

Some of the wood may pass through the digestive tract of the catfishes, but it's passed without metabolizing much from it...perhaps like the way chickens  consume gravel, or whatever (don't they? City boy here!)...or the way some marine Centropyge angelfishes "nibble" on corals in their pursuit of algae, detritus, and biofilms.

Again, my perusal of German's scientific paper seems to support this theory:

"Catfishes supplement their wood diet with protein-rich detritus, or even some animal material to meet their nitrogen requirements. Although I did not observe animal material in the wood-eating catfish guts, Pt. disjunctivus did consume some animal material (including insects parts, molluscs, and worms), and all three species consumed detritus."

And finally, the "clincher", IMHO: "The low wood fiber assimilation efficiencies in the catfishes are highly indicative that they cannot subsist on a wood only diet."



I mean, it's just one paper, but when he's talking about isotopic tracing of materials not consistent with digestion of wood in the guts of Loricariids, I think that pretty much puts the "eats wood" thing to bed, right? His further mention that, although some cellulose and lignin (a component of wood and our beloved botanicals!) was detected in the fish's fecal material, it was likely an artifact of the analysis method as opposed to proof that the fishes derived significant nutrition from it.

So what does all of this stuff mean to us? 

Detritus/biofilm/fungal growths = good. Don't loathe them. Love them.

I think it means that, as hobbyists probably knew, theorized, and discussed for a long time- that the Loricariids consume detritus, biofilms, and prepared foods when available. This is not exactly earth-shattering or new. However, I think understanding that our botanical-style aquariums can- and do- provide a large amount of materials from which which these and other fishes can derive significant nutrition furthers my assertion that this type of system is perfect for rearing and maintain a lot of specialized feeders. 

Materials like the harder-"shelled" botanicals (ie; Cariniana pods, Mokha pods, Sterculia pods, Catappa bark, etc.) tend to recruit significant biofilms and accumulate detritus in and on their surfaces. And of course, as they soften, some fishes apparently rasp and consume some of them directly, likely passing most of it though their digestive systems as outlined in the cited study, extracting whatever nutrition is available to them as a result. This is likely the case with leaves and softer botanicals as well.


The softer materials might also be directly consumed by many fishes, although the nutrition may or may not be significant. However, the detritus, fungal, and microorganism growth as a result of their decomposition is a significant source of nutrition for many fishes and shrimps.

Detritivores (of which the amount of species in the trade is legion), have always done very well in botanical-style aquariums, and the accumulation of biofilms and microbial growth is something that we've discussed for a long time. By their very nature, the decomposition and accumulation of botanical materials make the "functional aesthetics" of our aquariums an important way to accommodate the natural feeding behaviors of our fishes.

So, the answer to the question (literally!), "Who has the (literal) guts for this stuff?" is quite possibly, "everyone!" 

I mean, what aquarist doesn't love the grazers, detritovres, and opportunistic omnivores? 

Stay studious. Stay curious. Stay observant. Stay engaged. Stay resourceful...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

June 19, 2019


Letting go...for a little while, anyways.

If you are like oh, 80% of the hobbyists out there, you tend to work pretty damn hard to make sure that you're doing all that you can for your fishes to keep them healthy and their environment stable. Of course, on occasion, life gets busy, and you might have stretches of times where you're simply not able to take care of your aquarium(s) as perfectly as possible.

Life happens.

With our botanical-focused natural aquariums, what happens when say, we skip a water exchange or two, a filter media replacement, or if we can't feed as often as we used to, or..? 

Is it a big problem?

I mean, you have a tank filled with a significant amount of slowly decomposing leaves, botanicals, etc., which contribute the the bioload of the aquarium. That amount of material has to have some impact on water quality, right?

It does, but not always in the way you might think.

It's hardly scientific; it's more like a "common sense thing"- but if you're careful about how much botanical material you add in the first place, and how quickly you add it, the impact of all of this material is more of a positive, IMHO. 

All additions of botanicals to an existing aquarium need to be measured, deliberate, slow, and considerate. You need to observe your fishes' reactions, monitor water chemistry, and stay alert to the changes and demands that botanicals will place on your aquarium. And they will. There's no mystery here. Adding a ton of stuff into any established aquarium creates environmental changes and impacts that cannot be ignored.

Are all of these impacts necessarily bad?

No, I don't think so.

If you think about it, these materials also function as a substrate- a "fuel", of sorts, for the growth of beneficial bacteria, biofilms, and other microorganisms within the aquarium. In my opinion and experience, when added gradually and methodically, you can look at all of this stuff as the biological "power station" for your tank, supporting a population of organisms which serve to break down more toxic compounds and substances via the nitrogen cycle.

I think it's sort of analogous to the use of live rock in a reef aquarium. Live rock is considered an essential component of a reef aquarium, because it serves as that aforementioned "biological filtration substrate" for the colonization of billions of gentrifying bacteria. This is something I'd like to see some more serious research on, because I think that there's "something" there.

So, what are the implications for us if our husbandry should slip now and then?

Will all of the botanical material continue to break down, keeping the water "tinted?" Will biofilms continue to colonize open surfaces? Will water chemistry swing wildly?  Will phosphate and nitrate accumulate rapidly? Will the aquarium descend into chaos?

Or, will it simply continue to function as usual?

It's my belief that it will.

I mean, when you think about it, the natural, botanical-style blackwater aquarium is sort of set up to replicate a habitat where all of this stuff is taking place already. Leaves, seed pods, etc. are more-or-less ephemeral in nature, and are constantly breaking down in these environments. Decomposition, accumulation of epiphytic growth, and colonization of various life forms is continuous. Now, I realize that an aquarium is NOT an open system, but for the sake of this little section of the habitat- the substrate, there are many functional analogies if you study it carefully.

How much more will things change by simply delaying water exchanges for several weeks? By not siphoning detritus at all? Will this really become some sort of problem? Or, will the bacteria, fungal growths, and other microorganisms and crustacean life living in our botanical substrates continue to do what they do- break down organic waste and reproduce?

I think they will. 

So...if you are in one of those "benign neglect" phases in the operational cycle of your aquarium, it's entirely possible that an established microfauna population (supported by extensive use of botanical materials) can act as a sort of "biological fail safe" for your tank. Sure, botanical-style natural aquariums are easy to maintain if you set them up and manage them correctly from the start.

Obviously, along the way, leaves and other botanical materials will impart chemical compounds, including lignin, sugars, carbohydrates, cellulose, and of course, the coveted humic substances and "tint-producing" tannins, during their submerged existence. The important thing to ponder when using leaves and botanicals is that you're likely to see an initial "burst" of the desired and less desired compounds shortly after they are submerged in the aquarium.

The extent and degree to which these compounds are imparted to the aquarium depends on numerous factors (environmental conditions, the age and condition of the leaves and botanicals, the presence of "shredders" snd "grazers" in your tank), and the extent of your preparation process. And of course, your microfauna population will adjust and grow according to the available food sources.

However, not entirely "set and forget" systems; however, they are capable of running relatively unattended- IF-you apply common sense to them. In other words, don't over-populate your tank. Don't feed excessive amounts of food. Don't forget to engage in regular maintenance (ie, those water exchanges, replacement of filter media, etc.).

Be smart.

Stay diligent. Stay inquisitive. Stay observant. Stay methodical. Stay habitual. Stay engaged...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




June 18, 2019


Parallel Processes- Beneficial Practices...

The world of natural, botanical-style aquariums is, not surprisingly, emerging as not only aesthetically unique, but with a functional aspect that sets them apart from many other aquarium systems you could operate.

In my "infinite" down time (which is only like when I'm about to doze off, or so it seems these days), I often think of how some of the practices that we engage in as hobbyists are really analogous to many of the processes that occur in nature. With my near obsession with trying to replicate as many natural process and functions as possible. It's hard for me not to think of a few which really come to mind.

The most obvious is adding (or removing) leaves and botanicals to our tanks. Simply tossing (actually, literally) in some leaves mimics- very realistically- the process of "leaf drop", which has occurred in natural aquatic habitats as long as there have been trees! Now granted, many of us as hobbyists want to employ a bit of aesthetics and "place" them more carefully, but the analogy is the same. 

And of course, when leaves fall into the water in Nature, they begin their gradual decomposition. The nutrients bound up in the leaves helps replenish minerals and nutrients which are often depleted over time. There is a more or less continuous supply of leaves falling into jungle streams, which is why you'll see leaves at varying stages of decomposition in streams, It's also why leaf litter banks may be among the "permanent" structures in many tropical aquatic systems.

For our aquariums, you could conceivably apply some methodical "process" to this by dropping your leaves in greater quantities at certain times of the year, to mimic seasonal abundance. Or, changing the varieties of leaves that you place. And varying quantities. I have this thing where I make it a point to add 1 to 2 leaves every day into a tank...I literally will toss them in, and "let the chips fall where they may."

Now granted, I might move them around later...lol.

(Interesting side observation: When I drop in a leaf, the fishes literally could care less. Like it's a regular occurrence in their world (as it IS) and they are somehow "programmed" not to freak out about "botanical bombs" falling into their midst.)

And lets be honest, if you have any water movement in your tank, stuff blows around and re-distributes...Just like what happens in nature, when currents conspire to do the same thing. In fact, in one large botanical-style tank I did a few years back, the prevailing water flow would act to create a submerged "litter bank" in one particular corner of the tank...which was incredible! I would often find my pair of Apistogramma cf. regani guarding a clutch of fry in that "bank!" Kind of like what they'd do in nature!

Natural leaf litter banks are amazingly interesting structures...ripe for aquarium replication!

And of course, when you remove botanicals and leaves (like, if you're one of those hobbyists who has issues with the appearance of stuff decomposing in your tank...), or if you let it decompose-you're also sort of replicating a process in which material does the same thing in nature. These materials will impart their bound-up humic acids, tannins, and other compounds as long as possible, then ultimately, simply serve as a "substrate" for microorganism and algal growth...Just like in nature.

The time-honored practice of water exchanges is the ultimate "environmental hack"- as well as the most faithful parallel to what happens in nature. Rainfall, and the influx of new water from flooded forest areas, overflowing streams, and runoff.

The wet season in The Amazon, for example, 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! 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?

That's a cool cocktail party sound bite and all, but what happens to the (aquatic) environment in which our fishes live in when it rains?

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 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. 

All of the botanical material- fallen leaves, branches, seed pods, and such, is suddenly submerged. And of course, currents re-distribute this material into little pockets and "stands", affecting the (now underwater) "topography" of the landscape. Leaves begin to accumulate. Tree branches tumble along the substrate.  Soils dissolve their chemical constituents, tannins, and humic acids- into the water, enriching it. Fungi and micororganisms begin to multiply, feed on and break down the materials. Biofilms form, crustaceans reproduce rapidly.  Fishes are able to find new food sources; new hiding places..new areas to spawn.

Life flourishes.

The environmental impacts of an influx of fresh water are equally as beneficial in the closed confines of our aquariums via water exchanges. Not only do you dilute and export excess organic wastes, you have the ability to maintain as much as possible the consistent concentration of tannins and humic substances.


Now, sure, we don't really have a reliable means to measure and reference what these concentrations are, but we can employ consistency and at least duplicate what is working for us. In other words, if in your 5-gallon makeup water container, you find that 5 catappa leaves and two pieces of catappa bark give you the right characteristics (visual tint and pH in range), it's at least starting point, right? You do the same thing over and over again and that's your baseline...one way of keeping your environment consistent.

As much an "art" as a "science." Yeah, it's a crude start...But it's a start.

Even the selection of botanicals we use in our aquariums can be a sort of analogy to what happens in nature. As biotope enthusiasts will attest, having the correct materials in your tank not only looks right- it serves to more accurately replicate the habitat that you're obsessed with...

It's at least a valid question to ponder whether we as hobbyists can, at least in theory, if not in practice-impart some of the same botanical substances into the water as the fishes might encounter in their natural habitat when we utilize the actual leaves and botanicals that occur there!

Interesting...like, sort of the way utilizing specific probiotics  do certain things...would it not make some sense to hypothesize that using the specific botanical materials that are found in the fish's natural habitats in our tanks will provide many of the same benefits they'd receive in the wild?

Again, a lot of questions; a healthy dose of assumptions...but a really cool "track to run on" for the ambitious and inquisitive natural-style aquarium geek!

These are just the most immediate parallels/analogs which come to mind, but you get the idea. In overall aquarium practice, there are many. In the natural, botanical-style aquarium arena we operate in, the possibilities are endless...and the opportunities for advancement are numerous!

I get stupidly excited just contemplating this stuff!

It's another "mindset shift" we can make as "Tinters"...not just in accepting a different aesthetic or way of doing things...but in understanding that WHAT we do and HOW we do it can have implications beyond the superficial and obvious. And in the process, perhaps gaining a greater understanding of both our fishes and the amazing (blackwater/brackish, etc.) habitats from which they come.

Stay motivated. Stay diligent. Stay curious. Stay resourceful. Stay observant...

And Stay Wet!


Scott Fellman

Tannin Aquatics 

June 17, 2019


Unfiltered Nature.


Ohh! A Monday rant- filled with potentially divisive opinions and controversy? Don't say I didn't warn ya'!

Let's get to it.

Nature is a very random place.

Sure, it has a certain "order" all its own, but for the most part, Nature creates her own patterns, designs...conforms to no "aesthetic" but that which arises out of her very existence. Nature is filled with purpose, intent, and the results of tortuous environmental processes stretched out of eons. The result is beauty that humans can only admire and hope to recreate on some level.

We seek order in an otherwise disorderly, decidedly "dirty" place. When we try to interpret Nature's "design", we tend to overthink it. Many of us  tend to observe and distill and edit elements that appeal to our aesthetic sensibilities, as opposed to study and attempt to understand just what it was that makes a certain scene look the way it does, and to replicate Nature as it really is- raw and unfiltered.

And there's that strange hobby "malapropism" that has pervaded the aquascaping world, in my opinion. A way that we interpret things that is a bit, well- odd to me:

Looking at a mountain or a forested canyon and using that for inspiration for an aquascape is not exactly what we think of when we talk about a "natural aquarium." No, in our opinion, the term "natural aquarium" refers to a system which attempts to replicate aspects of the aquatic environment as it exists in Nature.  It's not about scaling down a mountain range in Yunnan province in China or wherever, covering some rocks with moss, and calling your work a "natural aquarium."

Yet, this seems to be proferred as such in many parts of the hobby. And it's a damn shame, IMHO. At the very least, it's a very inappropriate use of the term that might be confusing to some.

Opinionated much, Fellman? Absolutely. Hung up on semantics? Maybe. Overly harsh? Perhaps. Think your opinion is accurate and important? Hell, yes.

Words matter. 

Let me clarify my opinion:

There is absolutely nothing wrong with interpreting and utilizing inspiration from Nature however you choose in your aquascaping work.  Nothing. The results of a "diorama" style can be beautiful. However, the problem comes when we endeavor to communicate to the uninitiated that this type of aquarium is "based on Nature" -as if a carefully-contrived "diorama mountain range" comprised of Glostostigma-covered rocks is what a natural aquatic habitat looks like.

That is where it gets a bit weird, IMHO.

What was ever not good about looking at a stream, flooded forest, pond, or bog, and attempting to replicate it accurately as it is-both in form and function- in our aquarium? To replicate it without overly stylizing and "ratio-ing-out" every rock, every twig, every plant? What is it about the actual appearance of so many aquatic ecosystems that has the bulk of the aquascaping world somehow avoiding replicating them?

Is scaling down a mountain, or creating a "sanitized" version of some elements of a genuine aquatic habitat the best we can do? Is creating an aquarium based on Nature as it actually is just not "good enough" as an art form for us?

Is it because it doesn't "measure up" somehow to the "fantasy forest scape" that the guy did in that last big contest, in terms of perceived  effort,"creativity" or "interpretation?" Is it because that in Nature, the water isn't always crystal-clear, blue/white? Is it because the bottom of many natural aquatic habitats are covered in decomposing leaf litter, tree parts, and twigs? Because it's not clean and neat and tidy and "Iwagumi-friendly?" Yeah, It's often dark, disorderly...unpredictible.

Can we not handle that?

Or is it something even weirder than that?

Could it be that many aquascapers are hesitant to replicate "unfiltered Nature" because it's not "designed enough?" Because it's "already been done" (by, like, oh, I don't know-the freakin' UNIVERSE!), and therefore not "original" is some strange manner?" Because somehow, something in our minds tells us that we have to "one up" Nature, as it doesn't "measure up" to our aesthetic goals and interpretations?

To me, it seems like many 'scapers seem to feel that Nature is somehow "flawed" because it doesn't conform to what WE feel a "natural" aquatic scene should look like. Somehow, "Iwagumi" rock arrangements are embraced as "Nature", and Nature itself takes the proverbial back seat.

If you really think about this, it's not hard to arrive at such conclusions. When was the last time an aquarium which looked a lot like a real natural aquatic habitat won one of those big contests?

Yet we think nothing of scaling down a whole mountain range and calling the resulting aquarium "Nature"...That's not a bit odd for an aquarium? Nothing weird there, right?

Have we gotten too full of ourselves? Or are those natural aquatic habitats simply too "artistically flawed" for us to incorporate in our aquariums?


There are no "flaws" in Nature's work, because Nature doesn't seek to satisfy observers. It seeks to evolve and change and grow. It looks the way it does because it's the sum total of the processes which occur to foster life and evolution.

We as hobbyists need to evolve and change and grow, ourselves.

We need to let go of our long-held beliefs about what truly is considered "beautiful." We need to study and understand the elegant way Nature does things- and just why natural aquatic habitats look the way they do.  To look at things in context.  To understand what kinds of outside influences, pressures, and threats these habitats face.

To understand why the fishes which reside in them live in specific niches...

Perhaps, with this understanding and appreciation for Nature as it really is finally in hand, we can move further forward... And truly blur the lines between Nature and aquarium.  For the benefit of all.

We believe that people are wildly curious about the natural world, yet people also tend to over complicate the unknown, and polish out the beauty of Nature. There are no rules to rediscovering the unfiltered art beneath the surface. We believe in the preservation of the "patina" of biocover found on submerged surfaces, and in fostering the appreciation of the ephemeral components of Nature- leaves, wood, and botanicals...

We play at the "delta" at the intersection of Nature and art. 

We celebrate aquariums modeled after Nature as it really is, in form and function: Filled with randomness, intricacy- perhaps even a bit of mystery. A special character that only an aquarium which replicates Nature in this manner can fully achieve.

Perhaps we can give it some more consideration? Maybe we can look at a few pics of a wild aquatic habitat as a possible influence for our next aquarium? Am I too blasphemous here?  I don't think so. Read some early Takashi Amano writings and see if you agree. Don't read the "cargo cult"-style fanboy homage drivel that's everywhere now. Go to the actual source.  Google it. Find his older works and READ his words. 

Perhaps it's time for us all to "double down" on Nature as it is. Again.

Yeah. It is.

There is beauty there. Unimagined intricacies and details and wonders...all of which can be incorporated into an aquatic display...If we accept Nature as it is.

Are you a bit wound up today, Fellman? Yeah, I think I am. 

Until next time...

Stay original. Stay bold. Stay unbounded. Stay creative. Stay observant. Stay appreciative...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


June 16, 2019


Do your Tetras know?

I suppose I am one of those deeply philosophical hobbyists. 

The other day, a fellow aquarist and I were talking about managing our aquariums, and the conversation turned (as it inevitably does when my friends talk to me) about the idea of utilizing natural materials (ie; wood, botanicals, etc.) in our aquariums, and where the practice fits in the grand scheme of trying to recreate the habitats from where our fishes come.

And of course, my mind wandered a bit...

One of the things I have always loved about keeping aquariums is that you have this wonderful glass or acrylic box, filled with water, wood, hardscape materials, and fishes, and to the animals which reside there, it becomes their whole universe.

Yeah, kind of "meta", I know, but...

Ever look at it that way?

I mean, even at the hobby's most "basic" levels, you as the aquarist create the physical environment for your fishes, and are more or less in control of every facet of its existence. You control the appearance, environmental parameters, population, input and export of nutrients- like, everything. And the health and lives of each and every organism which resides in the aquarium are completely in your hands.

Kind of an awesome responsibility, when you think about it that way, huh?

It is.

And, while our fishes go about their daily existence likely not comprehending all of that, and likely behave in your aquarium in much the manner that their wild ancestors have for untold millions of years, what they DO know is that this is their world. The physical structures you've created, the competing population of fishes, availability of food resources, and the quality of the water are just a few of the things they contend with like they would if they were swimming about in the wild.

This is one of the reasons why I have had a near-obsession with attempting to recreate, to some extent, as many of the physical/environmental characteristics of their wild habitats as possible for the fishes under my care. All the while, realizing that, although they will be residing in a closed system with many physio-chemical characteristics similar to what they have evolved to live under, it's not a perfect replication, much though I might want it to be, and being of the opinion that replicating "some"of these characteristics is likely better than replicating "none" of them.

An arrogant assumption on my part, I suppose. I mean, like every one of you, I'm fully responsible for the animals which I keep. And I take a certain degree of pride in that. I want the best for them.

That being said, I'm personally not in that mindset of having to be absolutely "hardcore" about being 100% accurate biotopically, in terms of making sure that every leaf, every twig, every botanical is from the specific habitat of the fishes which I keep. I do respect aquarists who do, however. But that's not me. Rather, I place the emphasis on providing a reasonably realistic, "functionally aesthetic" representation of the habitat form which they come, with aquascaping materials, layout, and environmental parameters as close as possible to the parameters in the wild.

You can be a very responsible owner without obsessing over making every micro-semion of conductivity, or every ppm of phosphate in your tank match that of your fishes' wild habitat. I'm pretty confident about that.

Your fishes likely don't know that, having been captive-bred for a few generations, or collected from their natural habitat and being subjected to varying environmental differences along the chain of custody from stream to store. The likely don't even care. They're likely just happy to be somewhere stable by the time they arrive in your home aquarium!

IMHO, being genetically "programmed" by evolution to live under certain environmental parameters for millennia can't likely be replaced by a few dozen generations of captive breeding. However, being able to acclimate and thrive-even reproduce- in conditions significantly different from what they evolved under does indicate some good adaptability on the part of our fishes, doesn't it? 

And as an aquarist, we benefit from this, even though our hearts may tell us it would be a cool idea to try to be 100% faithful to nature in this regard. I know that I do!

Of course, all the while being fully aware that, for example, achieving and managing a 4.3 pH similar to the floating leaf littler banks of the Aliança Stream (a tributary of Branco River in Brazil), for example, is beyond the level of detail that I want to go into!

It would be very cool to do, but it's just not what I'd want to do at the moment.

I suppose my attitude towards those factors would "disqualify" me personally from being a very hardcore biotope aquarist- at least one who would try to compete and win in a contest! 

The Tetras I keep, of course, don't know this.

Nor do they seem to care.

Rather, they're obsessed (are they?) with finding their next meal, socialization, and other more mundane aspects of their daily existence. As long as they are physically comfortable and free from high levels of stress as a result of evading predators and exploiting very limited food resources, I don't think one could make an argument that they do...

And just because you're content with your aquariums being "biotope-inspired" as opposed to 100% faithful to the natural habitat you're into doesn't mean you don't care, aren't doing a good job, or aren't dedicated to your craft.

What every Tetra, cichlid, Gourami, Pleco, or any other fish under your care does know is that they are living in a stable, stress-limited environment that they can easily adapt to and live out their lives in.

And that is worth considering the next time you set up an aquarium.

Now, really-do your tetras and cichlids and gouramis know this?

I think so.

Give yourself a pat on the back for doing what you do so well. I think that your fishes would, if they could. You're doing a pretty kick-ass job.

That's also what every Tetra knows.


Stay inquisitive. Stay inspired. Stay enthusiastic. Stay dedicated. Stay relentless...

And Stay Wet.


Scott Fellman

Tannin Aquatics



June 15, 2019


Accepting the "challenges"...if you want to call them that..

I think that the biggest challenges in creating a botanical-style aquarium involve the processes- that is, understanding and accepting the processes which occur to get one of these systems "broken in" and thriving. Now, none of the stuff we do is difficult, from a "procedural" standpoint; it's mostly "just prep, place, and wait." The hard parts are deploying patience and making the mental shifts required in the botanical-style aquarium game..

The mental shifts being (for the millionth time, right?) acceptance of a different aesthetic, appreciating biofilms, tannin-stained water, detritus, and organic decay of botanical materials. Understanding that these are the elements of Nature, truly "unfiltered"- and that many (dare I say most?) natural aquatic habitats of the world incorporate several of these elements. Realizing that Nature is not the perfectly arranged, color-coordinated, "golden-ratio"-driven environment that we as aquarists tend to interpret it as.

Back to the process, for a second.

Now, obviously, you're utilizing terrestrial materials in an aquatic environment. Seed pods, stems, leaves, etc. all tend to float initially when wetted. This is part of the reason why we employ a soak/steep/boil for most botanicals. Otherwise, if you just drop 'em in your tank, you'll end up with the botanical equivalent of the Sargasso Sea- a floating "salad" of botanicals topside!

These prep processes help saturate and sink the botanical materials. Some sink more easily and quickly than others. The more durable, "hard-shelled" pods can take an hour or more of boiling just to get them to stay down (I'm thinking about Cariniana Pods and Sterculia Pods here). Their tissues are hard and not the most porous, so the extended soak/boil/steep period is essential if you want them to sink. And of course, as touched on before, this will also release any pollutants bound up in the surface tissues of these botanicals.

Once the botanicals are no longer buoyant, they easily sink to the bottom of your aquarium. And of course, they will begin releasing tannins, humid substances, lignin, and other organic compounds that are present in their tissues. The tannins and humic substances which we covet are just a small part of what is rebased into the aquatic environment, and when you're adding a bunch of material to the aquarium, it's important to observe water quality. We always tell you to go slowly for this very reason- particularly in an established aquarium. These are "dynamic" materials.

After several days or a week, you will see the materials appear to "soften up" just a bit, and perhaps acquire a "patina" of biocover. Most likely, it's in the form of fungal growth and biofilms. These biofilms, in particular, are an incredibly important part of the aquatic ecosystem we aim to replicate in our aquariums, but their appearance is often outside of the aesthetic tastes and expectations of the uninitiated hobbyist!

Your fishes, of course, will have a slightly different opinion...

And of course, the tinted water that seems to accompany our use of botanicals...well, that's a BONUS, in my book! 

Yeah, this period is a part of the "game" where we can separate the hobbyists who understand what's really natural from those who have "not done their homework", so to speak. As we've discussed numerous times, biofilms are a completely natural and expected part of utilizing dried botanical materials in an aquarium. The "aesthetics" of this process is not everyone's idea of "beautiful"- and that's understandable.

However, it's a normal, natural, part of the game. 

Biofilms will always be present to some extent during the lifetime of your botanical-style aquarium. We need to accept this. During the initial phases, you have several options. You can physically scrub the biofilms off of the botanicals as needed (accepting the fact that they will likely reappear), or observe your natural "biological controls" (such as ornamental shrimp, snails, or even Otocinculus catfish) to help with this process.  

In fact, many fishes will forage upon biofilms as part of their diet. Although they are efficient, you shouldn't expect the animals to get everything, and you should not stock your tank with "scavengers" for the sole purpose of eliminating these growths. You can assist with the removal of any offensive materials or...wait it out.

The realization that it's perfectly natural and entirely consistent with the nature of these environments to have some of this stuff present is likely little comfort to you if you just can't handle looking at a field of "yuck" on your botanicals. I can't stress enough the need to make that "mental shift." As we discussed, management of this stuff is entirely up to you and what you can tolerate. Generally, the biofilms, fungal growths, and algae are self-limiting, ultimately disappearing over time as the compounds that fuel them diminish or attain levels that are not sufficient for their growth, or as a result of animals consuming them- or a combination of both.

Ultimately, if you continue to deploy patience and a healthy dose of good old-fashioned aquarium husbandry skill (ie; water exchanges, etc.), your aquarium will fall into a delightful "equilibrium" of sorts- with the botanicals regularly breaking down and transient appearances and disappearances of fungal growths and biofilms during the lifetime of the system.

And of course, that decomposition...the breakdown of botnaicals and leaves is an ongoing process. The decomposition of "transient" materials like leaves and softer pods, etc. is simply part of the natural dynamic, and will continue as long as you choose to employ these materials in your aquascape. If you observe carefully, you may note spawning and other "grazing" behaviors in your fishes, and note that they are spending significant time foraging though the broken-down matter, much like in nature.

Ultimately, the decision to create a "botanical-style aquarium is as much a philosophical one as it is a practical one. To accept nature, rather than to fight it, is a bit at odds with the mindset many of us have with regards to aquarium keeping. As you begin to understand and evaluate your own aquarium, you'll gain a greater appreciation for the wonders of nature, and the processes that have occurred for eons.

Challenge? Perhaps. But the rewards of accepting the challenges could be beyond measure. Rise up to them...

Stay bold. Stay diligent. Stay curious. Stay observant. Stay progressive. Stay enthralled...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

June 14, 2019


Fine-tuning "the practice..."

As a fanatic about truly natural-style aquariums; one who embraces the nuances of the wild habitats- the aesthetic, the function, the color of the water- you're very well attuned to everything that the use of botanical materials can bring to your tank.

Our "practice" of botanical-style aquariums is becoming more and more "mainstream" all the time, with hobbyists from all sorts of aquatic disciplines dabbling with, and incorporating botanical materials into their work. Some are doing it purely for the aesthetics; some for fish breeding, others for the adventure- and some simply want to do some cool experimentation!

When people ask me why I like to add leaves to my aquariums, I can probably give hem a dozen or more reasons why; among the most important is for the ecological "enhancements" they offer as they break down.

Regardless of YOUR rationale for adding "stuff" to your tanks, it's important to follow some basic "best practices" that those of us in the game for a while have learned- sometimes, painfully, I might add! One of those is to go SLOWLY when adding materials to an established aquarium.

I know, I know. We must have mentioned this literally 5,000 times in they blog and elsewhere- but it's fundamental to what we do.

It seems logical, but in practice, it's not always that easy to restrain ourselves, right? I mean, it's just a bunch of leaves and stuff...What could go wrong?

Well, a lot, if we're less than careful!

Think about what happens when leaves and botanical materials fall into streams and other bodies of water in nature.

When leaves fall into streams, field studies have shown that their nitrogen content typically will increase. Why is this important? Well, for one thing, scientists see this as evidence of microbial colonization, which is correlated by a measured increase in oxygen consumption.


This is interesting to me, because the rare "disasters" that we see in our tanks (when we do see them, of course, which fortunately isn't very often at all)- are usually caused by the hobbyist adding a really large quantity of leaves and botanicals at once to an established, stable aquarium, resulting in the fishes gasping at the surface- a sign of...oxygen depletion?

That makes sense, right? 

These are interesting clues about the process of decomposition of leaves when they enter into our aquatic ecosystems. They have implications for our use of botanicals and the way we manage our aquariums. I think that the simple fact that pH and oxygen tend to go down quickly when leaves are initially submerged in pure water during lab tests gives us an idea as to what to expect in aquariums..

Rapid changes. 

And to an aquarist, rapid changes in the environment = bad news.

A lot of the initial environmental changes will happen rather rapidly, and then stabilize over time. Which of course, leads me to conclude that the development of sufficient populations of organisms-beneficial bacteria- to process the incoming botanical load is a critical part of the establishment of our botanical-style aquariums.

Fungal populations are also important in the process of breaking down leaves and botanical materials in water as are higher organisms, like insects and crustaceans, which function as what ecologists call "shredders." So the “shredders” – the animals which feed upon the materials that fall into the streams, process this stuff into what scientists call “fine particulate organic matter." 

You know, "detritus" and "stuff in the water."

In studies conducted in tropical  rainforests in Venezuela, decomposition rates were really fast, with 50% of leaf mass lost in less than 10 days! Interesting, but is it tremendously surprising to us as botanical-style aquarium enthusiasts? I mean, we see leaves begin to soften and break down in a matter of a couple of weeks- with complete breakdown happening typically in a month or so for many leaves.

And biofilms, fungi, and algae are still found in our aquariums in significant quantities throughout the process- just like in nature.

The wild habitats that we are fascinated by are highly dynamic environments, and change continuously.  They're constantly evolving, accumulating new materials, and creating new physical habitats for fishes to forage among. These new food sources and chemical/energy inputs are important to the biological diversity and continuity of the flooded forests and streams of the tropics.

We replicate this process in the aquarium by adding new botanicals, conducting water exchanges, etc. The basics of aquarium husbandry and management haven't really changed in a century. And they are just as applicable to the botanical-style/blackwater aquarium as any other. The only real "difference" here is in the context- and how we understand what is actually going on and why.

Mental shifts.

We are not managing aquariums to be sterile glass boxes, "dioramas", or "zen gardens." It's not just a "look." We are understanding that a real "nature/natural-style aquarium" embraces the processes of nutrient import/export, decomposition, bacteria/fungal growth, and long-term nutrient utilization by the organisms which we keep. The appearance is far different than a system strictly set up for aesthetics. Rather, our systems offer a unique combination of form AND function...what we call "functional aesthetics."

The "look" and the "function"- working hand in hand to create a replication of Nature far more authentic than what we've done in the past in the hobby. And what is required to execute this?

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

Stay studious. Stay patient. Stay diligent. Stay observant. Stay creative. Stay adventurous. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics