June 12, 2020


After a rocky start, it's back to the bottom for us!

Well, if you've noticed lately, we're really starting to phase out rock on our website! It's pretty obvious...We've been blowing the stuff out at ahem, "rock bottom" prices lately to get rid of it! Surely you noticed, because we've never sold so much rock so quickly! Weren't aware? Well, you'd have to be "sleeping under a rock" to- okay, that's enough already!

Seriously, though, I'm finished with rock...at least, finished with selling the stuff on our site. (although we'll keep our "River Stones" and River Pebbles", 'cause I like them and they make sense!). Is this a sudden backlash against rock or something? Not really. I just don't like handling, sourcing, shipping, and selecting the stuff. It's a pain in the ass: expensive to ship, highly subjective to select, and difficult to get a good mix of sizes from our suppliers...so I'm done.

It also reminds me of things I hated about the coral trade...too many stupid names to keep up on, a lot of hype about any rock that some superstar 'scape uses, and a sort of lack of "romance" to me.

Oh, and the best reason?

It really isn't all that applicable to what we do.

As we delve deeper into the world of blackwater, botanical-style aquariums, I think it becomes more and more important for us to understand the wild blackwater habitats of the world. Specifically, how they form, and what their physical characteristics are. It's easy for us to just go the  "cliche' route" and say that blackwater is water, "...which has a low pH caused by dissolved organic materials and looks the color of tea."  You could just leave it at that. You know, the standard line used for decades.

Not untrue, but not really all that helpful in understanding exactly what it is, IMHO.

And more important, not helpful in understanding why it has these characteristics.

And there are some things which contribute to the overall habitat of blackwater environments- specifically, how they form.

Well,interstingly, it does sort of start with the study of rocks...Geology.

Hey, don't start yawning on me...

I should first start of by freely admitting that I sort of- well, dozed through the limited number of geology classes I took in high school and college, and never knew that the time I spent in those classes drawing pictures on the back of my notebooks and trying to figure out where to get the stuff I needed for that weekend's party would ever come back to haunt me decades later, when I'd have to re-familiarize myself with all of this stuff!

So, my understanding is limited, but I'll convey what I DO know to you here...And how it relates to our area of interest.

Blackwaters in areas like Amazonia (one of our fave locales, of course!) drain from an area known to geologists as the "Precambrian Guiana Shield", which is comprised of sediments include quartz, sandstone, shales, and conglomerates, stemming from the formation of the earth some 4.6 billion years ago. As a result of lots of geological activity over the eons, a soil type, consisting of whitish sands called podzol is formed.

Podzols typically derive from quartz-rich sands, sandstone, and other sedimentary materials in areas of high precipitation. (Hmm, like The Amazon!). Typically, Podzols are kind of shitty  for growing stuff, because they are sandy, have little moisture, and even less nutrients!  

A process called podzolization (of course, right? What the fuck else would you call it?) occurs where decomposition of organic matter is inhibited. Numerous microbes and plants consume some of the nitrogen, and while eaten by other organisms, convey what's left to the even lower-lying forest habitats.

The Amazonian blackwater rivers are largely depleted in nutrients, having passed through the lowland forest soils as groundwater, from which weathering has already occurred. As a result, layers of acidic organics build up. With these rather acidic conditions, a deficiency of nutrients further slows down the decomposition of organics. So, yeah- lousy soil for growing stuff...But guess, what? They form the basis of the substrate in many Amazonian aquatic habitats! 

And the water which flows over this soil is what we call "blackwater",  which achieves it's unique color from a really high content of dissolved  humic substances- poor in nutrients and electrolytes. It's characterized by having sodium as one of its major cations (ions with fewer electrons than protons, giving them a positive charge), which means it has low alkalinity. Typically, the pH and electrical conductivity values are less than 5.0 and 25 μS cm–1, respectively (pretty freakin' low!).

So, to make a very long and intimidating story short, the physical characteristics of blackwater habitats are influenced as much by the geology as anything else!  

That is to say, all of the dissolved humic substances which give these bodies of water their unique look are "enabled" by the geological properties of the region. And from the "trace element perspective" (the reefer in me), only Fe, B, Sr, Pb and Se present consistent concentration variabilities sufficient to influence the chemistry of these waters...Like, this water has very low concentrations of trace elements.

That's why you'll often see simple fine, white silica-type sands on the bottoms of so many Amazonian streams and rivers. They originate up in the Andes mountains and are transported by various means into the lowland areas. I mean, there is way more to this process than I can convey here- but it's a study in the relationship between seemingly unrelated elements and how they come together.

Now, I admit that this is probably more than you will ever care to know about how sand works in your fave blackwater habitats, but I think it's important to understand that it's all kind of related. In fact, it makes it a lot easier to understand how blackwater systems came to exist and function when you consider this "big picture" stuff!

And of course, we're a hell of a lot more interested in the "decaying vegetation" (you know, the leaves, twigs, seed pods...stuff like that!) which influences the waters.

So, using a quality substrate material which doesn't impact the pH or buffering capacity of the water to any great extent is important...The reality is that just having an awareness of what goes on in the natural aquatic habitats we love gives us a nice "leg up" on this stuff. You're obviously not going to use a strongly buffering substrate like aragonite or whatever to do the job in your low pH and alkalinity blackwater aquarium, right?

And then there is that question about utilizing rocks in your "igapo" aquascape...

Like, why don't you find rocks in these habitats? 

As you know from my long-winded description above, I'm no expert-or even a novice- on geology or geochemistry, or anything in that subject area, for that matter....However, based on my research into this stuff, as related above, it goes without saying that these are hardly conditions under which rocks as we know them could form.

Oh, sure, you might find the random rock in the igapo that was washed down from the Andes or some other high-country locale in these forests, but it's a pretty safe bet that it did not evolve there. This also helps to explain why the blackwater habitats are generally low in inorganic nutrients and minerals, right? 

So...if you're really, really hardcore into replicating an igapo, you'd probably want to exclude rocks- especially if you're entering one of those biotope aquarium contests, astute judges would (rightfully) nail you on scoring for falling back on your natural inclinations as an aquascaper and tossing some in. 

I personally, of course, would be a bit more forgiving, but you won't find rocks in my igapo tanks!

Besides, there is something far more compelling and romantic about leaves, seed pods, and wood than there is about a bunch of rock, right?


Okay, don't answer that...

Yeah- you WON'T find any rocks in my "igapo" tanks...


I just can't say that I]m really into them.

Rather, we choose to concentrate on the more "ephemeral" components of the habitat, and rightfully so!

Our ability to mimic this aspect of the flooded forest habitats is a real source of benefits for the fishes that we keep- and a key to unlocking the secrets to long-term maintenance and husbandry of botanically-influenced aquariums.

The transformation of dry forest floors into aquatic habitats provides a tremendous amount if inspiration AND biological diversity and activity for both the natural environment and our aquariums.

Flood pulses in these habitats easily enable large-scale "transfers" of nutrients and food items between the terrestrial and aquatic environment. This is of huge importance to the ecosystem. As we've touched on before, aquatic food webs in the Amazon area (and in other tropical ecosystems) are very strongly influenced by the input of terrestrial materials, and this is really an important point for those of us interested in creating more natural aquatic displays and microcosms for the fishes we wish to keep.

Creating an aquascape utilizing a matrix of leaves, roots, and other materials, is one of my favorite aesthetic interpretations of this habitat...and it happens to be supremely functional as an aquarium, as well! I think it's a "prototype" for many of us to follow, merging looks and function together adeptly and beautifully.

Way sexier snd more interesting to me than any "Iwagumi" layout everyone drools about...Far more compelling than some "new" rock with a stupid name that people get all emotional about.

I like roots, twigs, seed pods, leaves, wood, and soils

Now, I think at least part of the reason why we're seeing success with utilizing botanicals in our aquariums is that fishes are instinctively "programmed" to utilize many of these materials as both feeding substrates- and as food items in and of themselves. (Yeah, "pellets and flakes" are NOT part of their natural diet... 😆)


Oh, but what about rocks in blackwater tanks? "Stay on topic, Fellman!"

Well, yeah, you CAN play with rocks in a blackwater aquarium. Nature has a prototype for THAT... You just need to study a bit.

In fact, you can have, rocks, leaves, wood and blackwater all together. It's just about context. It's about understanding how and why these materials come together, what factors conspire to cause this, and what can happen when it does.

Yeah, you can do it. You just won't be able to get many rocks from us! What are we going to replace our rock selection with? Something near and dear to my heart:

Substrate materials.

We've been busy formulating and testing some unusual substrates and creating variations that have not previously been offered in the trade before. Stuff that is perfectly suited for what us botanical-style, blackwater and brackish aquarium geeks do. Stuff that is designed to replicate, in form and function, the materials found in the natural habitats of our fishes.

So, for a lot of reasons, I think rocks are probably the least applicable materials we can offer...of course, the facts can go either way.

That being said...

A little research into these seemingly obscure, and perhaps unrelated topics can sometimes give us some awesome clues that can influence our aquarium practice in ways we haven't even imagined. Clues which may lead to further evolutions and improvements to our practices. Clues that can help us continue to create compelling aquatic displays.

So, when you see me unloading rocks at stupid low prices, you'll at least have a little bit of context, right?

I hope so!

Stay engaged. Stay intrigued. Stay curious. Stay diligent. Stay informed. Stay inspired...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

June 11, 2020


We told ya...really! Or, did we? I think so...

One of the great things about running Tannin is that not only do I get to curate and create a pretty cool selection of botanical materials- I have had the great pleasure of helping create and refine the technique and processes that we apply to use them in our aquariums. I didn't invent the idea. However, I think that I helped advance and perfect the idea.

I find it both an honor and a responsibility to do this.

And I take the responsibility very seriously...Myself and my team have spent years (decades, in my case) personally experimenting with a huge amount of botanical materials to create all sorts of aquarium systems with them. And during that time, we've developed techniques, guidelines, and "best practices" for using botanicals in aquariums. We've made some errors, and lost some fishes along the way, unfortunately. Hopefully, our experiences and lessons learned save others from these bad outcomes.

And, most important of all, we've made a huge effort to share all of this experience-the good, bad, and ugly-with you- our community, and the hobby as a whole- on this website, in this blog, our podcast, social media posts, several print publications, clubs, and on other podcasts. As loyal readers of this blog and listeners to this podcast know by now, I like to share stuff that happens around Tannin- the good and the bad- things we do well, and shit we screw up-because it may well give you insight into "what makes us tick", so to speak.

So, imagine my surprise when, the other day, I received an email from a customer who was quite upset about his botanicals developing what he called a "white algae" on their surfaces, and that they were apparently "rotting..." He went on to lament that he may have "wasted money" on his purchase, and that he was "...an unsatisfied customer..."

Woah- "unsatisfied customer"- that's like the worst thing I could hear as a business person! A nightmare scenario in my world, where your happiness is everything! What could have happened to precipitate this feeling? I immediately began to investigate to see what I could have done wrong, and what I could do to correct the situation. I reviewed the customer's order, the botanicals that were used in his pack, and the shipping time, etc.- all of the things that you'd do as a business person. Nothing amiss there.

Yet still, the customer was unsatisfied. While I initially thought it was nothing we did "wrong", the reality was that the customer felt he was somehow "wronged." And believe me- everything that goes wrong with your order, I assume is 100% MY fault.

All of it.

Regardless...something seemed amiss. It was obvious from the customers observations and the terminology he used in his email that something didn't go as expected. Could I have done something- anything- to have helped him avoid being disappointed?

Well, yes- and no...

Now, on the surface, I empathize with anyone who is experiencing something that they may not have seen before, or something which is outside of their understanding. Yet, when it comes to stuff like our botanicals, in this instance, it made me wonder? Why was this customer surprised? What expectations did he have of the botanicals before he placed an order? How did he NOT know that they are subject to recruiting biofilms on their surfaces, softening and ultimately decomposing, and  imparting a tint to the water? All of the things we consider fundamental and talk about obsessively in our world.

I mean, it's not like we don't discuss all of this stuff out there for all to see and learn about.

So, yeah, my very first instinct was almost defensive...

Fortunately, experience in this business and a little bit of instinct tells me never to just jump on someone when they complain. It's not just bad business- it's a stupid thing to do. I remember many times in the coral business, perusing online vendor forums on sites like Reef2Reef, and seeing how poorly some of our competitors handled customer complaints. Some were downright awful, publicly attacking the customer, etc., and I must admit, I sort of enjoyed the spectacle that usually arose when customers complained to certain vendors! It was often a real "train wreck."

Of course, when it happens to you, it's not all that funny. However, it IS a chance to make things right, perhaps win over a skeptic, and learn. IF you handle it right, and IF the customer can be "reached."

In this case, though, something told me that I was dealing with a customer who may have made one of the hobby's biggest and most common errors: "Leaping before looking." This was clearly someone who didn't have a clue what to expect. Just his terminology that he employed to describe what he was observing told me that. Where did the fault lie? Well, regardless, I can shoulder at least some of the blame. He somehow didn't see all of the information we put out.

What could I do about that?

Well, what I did in this instance was to explain to him that these occurrences are perfectly normal and part of what we expect in this game. I sent  links to a bunch of blog posts on the relevant topics of concern. My first thought is that, even though I may feel the messages and information are out there- they may simply be difficult for some people to find. They might be lost in the constant drumbeat of customers' pics of their cool tanks, etc. Maybe we need to do a better job on making the information even more available.

In fact, it's obvious that we do. We have to keep improving. Make it even more visible. Communicate more about how botanical-style aquariums work. For someone to have found our site, got excited enough to buy the products we offer, and then to NOT understand that what he was observing is perfectly normal is a definite issue for us to correct.

On the other hand, after thinking it over for a while, the disappointment of this customer was rooted in what I feel is an increasingly common problem in the hobby: Getting caught up in the hype and superficial aspects of something, and then just jumping in without doing some homework.

In our world, that means people seeing the cool look and unique benefits of botanical-style aquariums, without making the effort to study the functions, occurrences, and processes which we need to expect and embrace when creating these aquariums.

A lot of hobbyists (and I KNOW this, because I talk to a lot of them...) simply don't feel the need to learn all of the good, bad, and ugly of this stuff before jumping in. I mean, these aquariums LOOK so cool, and there are so many out there- they can't be that hard, right? Botanicals must stay pristine and clean and perfect forever, like an aquarium ornament or something...Because it's all about the LOOK, right? I mean, "..the guy's tank on Instagram looked so cool..."

That's the disconnect, IMHO. It's a real "pet peeve" of mine, too- as you probably know.

Botanical-style aquariums are not a "style of aquascaping."

They are a methodology- an approach- to keeping aquairums, and with the approach come unique functions AND aesthetics. The aesthetics being a small (but important and alluring) part of the whole thing, really.

And I think that it's a failing of me, the vendor and so-called "hobby authority"- because I need to find even better ways to get more of the information into the ultimate consumer's hands. Not just pretty pics and videos. My blogs, podcasts, and articles need to be MORE available. I'll work on it.

In general, it's also a failing of many vendors in the aquarium industry for trying to do all that they can to get people to simply purchase stuff without offering education in equal quantities. I say "many", because there are a lot of vendors that do a fantastic job of educating, too. Yet, there is ALWAYS room for improvement.


And finally- and perhaps most important- it's every bit as much about the individual hobbyist, who often jumps into something without making more than the most cursory, most superficial effort to learn more about what they are interested in doing in the hobby before jumping in. A lack of personal responsibility to educate oneself. This isn't a new phenomenon- it's been around for decades. I remember reading Tropical Fish Hobbyist when I was a kid, and a reader would write in about a tiny fish they purchased on impulse at the LFS, without knowing what it was, only to be just schooled by the magazine's editors because they bought a baby Gar, or something insane like that. 

I understand that, sometimes, it's okay to "learn on the fly"- that's fun for a lot of people...I know quite a few hobbyists like that. The kind who throw away the instructions for the new gadget they just purchased and jump right in and start "flipping switches and pressing buttons." And that's okay...I suppose. However, if you're going to leap before you look, shouldn't you at least consider what is supposed to be occurring?

I think so. 

So, yeah, I DO call BS on some of this.

I encourage every hobbyist to at least make SOME effort to understand what they're getting into before they go full speed ahead. In this age of Google and Facebook and tons of forums- there is simply no excuse for doing something in the hobby and being unpleasantly surprised when things go exactly as they're supposed to, because you didn't bother to do your homework. If you did, you'd know that what you're experiencing is, in our case- THE thing.

Yeah, I suppose I'm doing sort of the same thing that I used to laugh at in my coral days...sort of. Because the difference is that, although I put out what I felt is a ton of accessible information- I obviously didn't make enough of it -or make it more easily accessible-to reach this person on this occasion.

It's something I can work on. And I will.

And to my fellow hobbyists? Well he/she should get off his ass and read. That's my metaphorical "spanking." I mean, just because you might have to do a little search here to learn about something in the hobby that you're about to embark on, it doesn't mean that you're somehow a "victim" of marketing or something. There is no excuse for ignorance in today's world.

You need to educate yourself. You need to go beyond simply looking at pictures. You need to put in the work. And you need to know that- even if you study and go carefully- stuff can still go wrong.

We're dealing with Nature, and SHE controls the game. She dictates the process. She creates the aesthetics, and she determines the outcomes. Anyone who has kept aquariums for any length of time knows that you can do everything "by the book" and still fail. It's part of the wonder of Nature and the awesomeness of the Universe.

So what we can do- what we ALL can do- hobbyists, vendors, and lovers of aquariums- is to observe, learn, and SHARE our experiences. For the benefit of everyone.

Because nothing sucks more in the hobby than finding out after the fact that, if you knew all of the details, you may NOT have taken the leap quite so quickly. 

And to my disgruntled customer? Well, I haven't heard back yet. I hope that he reads the links I sent. I hope he goes deeper. I hope that he makes the effort to understand  what is supposed to happen in a botanical-style aquarium. I hope that he decides that this botanical-style aquarium thing, with all of it's unique function and unusual aesthetics- and benefits- is for him. I really hope that. Even if he gets his botanicals from someone else. It's bigger than just one company, one author, or one opinion on stuff.

It's an awesome hobby. A lifetime hobby. Please treat it as such, rather than a quick, easy thing to do on a weekend.

Educate yourself. Make use of the abundant resources out there. Even if you have to dig just a bit. Make Google your friend.Talk to fellow hobbyists. Reach out if you're not sure. Don't assume stuff. Don't let ignorance be your companion on the journey. Don't just rely on what you skimmed over or "heard..." Put in the work. You should want to- because just about anything that is cool and desirable requires some effort.

And yeah- we told ya' so.

Stay educated. Stay observant. Stay smart. Stay open-minded. Stay skeptical. Stay    engaged...

And Stay Wet.


Scott Fellman

Tannin Aquatics


June 09, 2020


The other benefit of botanicals: A supplemental food source?

The evolution of botanical-style aquariums is in full swing. Seems like we hear more and more every day from fellow hobbyists experimenting with botanicals in their aquariums.

Lately, we've been talking an awful lot about the environmental benefits of botanicals in our aquariums, and how they impart "functional aesthetics" to our systems. I think that's become not only more accepted in the hobby, it's backed up by a lot of scientific field studies, too. And, when we allow our aquariums to accumulate these materials as they do in Nature, the magic really happens!

What is also studied by science, but a little more "esoteric" in the hobby (IMHO) is the use of botanicals as supplemental food for our fishes and shrimps. 

Now, it's known that most plant materials have at least some nutritional value; or rather, they contain nutrients, vitamins, etc. which are known to be beneficial to aquatic organisms. Which ones are the best for use as "supplemental foods?"

Or, are they all pretty good? 


Well, here's the thing...

The thing that makes me curious is that most leaves and botanicals contain vitamins, amino acids, micronutrients, and other bioavailable compounds. The real question I have is exactly how "available" they are to our fishes and shrimp from a nutritional standpoint. And how "nutrient dense" these leaves and botanicals are? Do our fishes and shrimp easily assimilate all they need in every bite, or do they have to eat tons of the stuff to derive any of these benefits?

Big questions, right?

I mean, we as hobbyists sort of figure that if these things are present in the botanicals, then our animals get a dose of them in every bite, right? And, it begs the question: Are they really directly consuming stuff like Casuarina cones, or feeding on something else on their surfaces (more on this later)?

I think it's "yes" on both.

And the nutrition that they derive from consuming them?

Well, that's the part where I say, I don't know.

I mean, it seems to make a lot of sense to me...However, is there some definitive scientific information out there to prove this hypothesis?

A lot of the "botanicals for food thing" in the hobby (no, really- it's a "thing!") comes from the world of shrimp keepers. They've been touting this stuff in the hobby for a long time. A lot of it is based upon the presence of materials like leaves and such in the wild habitats where shrimp are found. I did some research online (that internet thing- I think it just might catch on...) and learned that in aquaculture of food shrimp, a tremendous variety of vegetables, fruits, etc. are utilized, and many offer good nutritional profiles for shrimp, in terms of protein, amino acids, etc.

They're all pretty good. Our friend Rachel O'Leary did a great job touching on the benefits of botanicals for shrimp in her video last Fall.

So, which one is the best? Is there one? Does it matter? In fact, other than sorting through mind-numbing numbers ( .08664, etc) on various amino acid concentrations in say, Mulberry leaves, versus say, Sugar Beets, or whatever, there are not huge differences making any one food superior to all others, at least from my very cursory, non-scientific hobby examination! 

Leaves like Guava, Mulberry, etc. ARE ravenously consumed by shrimp and some fishes. It's known by scientific analysis that they do contain compounds like Vitamins B1, B2, B6, and Vitamin C, as well as carbohydrates, fiber, amino acids, and elements such as Magnesium, Potassium, Zinc, Iron, and Calcium...all important for many organisms, including shrimp. Guava leaves are particularly good, according to some of the materials I read. Apparently, the bulk of the nutrients they contain are more "readily available" to animals than other leaves.

Well, that's pretty important, isn't it?

I think so!

Now, it may be coincidental that these much-loved (by the shrimp, anyways) leaves happen to have such a good amount of nutritional availability, but it certainly doesn't hurt, right?

Other leaves, such as Jackfruit, contain phytonutrients, such as lignins, isoflavones, and saponins that have health benefits that are wide ranging for humans. There is some conflicting data regarding Jackfruit's antifungal activity. However, the leaves are thought to exhibit a broad spectrum of antibacterial activity. In traditional medicine, these leaves are used to help heal wounds as well.

Do these properties transfer over to our fishes and shrimp?

Here's the straight answer: We are not aware of any scientific studies that have been completed to correlate one way or another. That being said, they seem to flock to these leaves and graze on them and on the biofilms which accumulate on their surface tissues. 


The "shrimp side" of the hobby reminds me in some ways of the coral part of the reef keeping hobby where I spent considerable time (both personally and professionally) working and interacting with the community. There are some incredibly talented shrimp people out there; many doing amazing work and sharing their expertise and experience with the hobby, to everyone's benefit!

Now, there are also a lot of people out there in that world -vendors, specifically- who make some (and this is just my opinion...), well - "stretches"- about products and such, and what they can do and why they are supposedly great for shrimp. I see a lot of this in the "food" sector of that hobby specialty, where manufacturers of various foods extoll the virtues of different products and natural materials because they have certain nutritional attributes, such as vitamins and amino acids and such, valuable to human nutrition, which are also known to be beneficial to shrimp in some manner. 

And that's fine, but where it gets a bit anecdotal, or - let's call it like I see it- "sketchy"- is when read the descriptions about stuff like leaves and such on vendors' websites which cater to these animals making very broad and expansive claims about their benefits, based simply on the fact that shrimp seem to eat them, and that they contain substances and compounds known to be beneficial from a "generic" nutritional standpoint- you know, like in humans.

All well-meaning, not intended to do harm to consumers...but perhaps occasionally, just a bit of a stretch.

I just wonder if we stretch and assert too much sometimes?

I'm not saying that it's "bad" to make inferences (we do it all the time with various topics- but we qualify them with stuff like,  "it could be possible that.." or "I wonder if..."), but I can't stand when absolute assertions are made without any qualification that, just because this leaf has some compound which is part of a family of compounds that are thought to be useful to shrimp, or that shrimp devour them...that it's a "perfect" food for them. 

It's just a food- one of many possibilities out there.

Of course, I hope I'm not out there adding to the confusion! We try to hold ourselves to higher standards on this topic; yet, like so many things we talk about in the world of botanicals, there are no absolutes here.

What is fact is that some botanical/plant-derived materials, such as various seeds, root vegetables, etc., do have different levels of elements such as calcium and phosphorous, and widely varying crude protein. Stuff that's known to be beneficial to shrimp, of course. These things are known by science. Yet, I have no idea what some of the seed pods we offer as botanicals contain in terms of proteins or amino acids, and make no assertions about this aspect of them, above and beyond what I can find in scientific literature.

However, I suppose that one can make some huge over-generalizations that one seedpod/fruit capsule is somewhat similar to others, in terms of their "profile" of basic amino acids, vitamins, trace elements, etc. (gulp). We can certainly assume that some of this stuff, known to have nutritional value, can possibly make these materials potentially useful as a supplemental food source for fishes and shrimps.

Yet, IMHO that's really the best that we can do until more specific, scientifically rigid studies are conducted.

Now, we may not know which seed pods and such in and of themselves are more nutritious to fishes and shrimp than others, but we DO know from simple observation that some are better at "recruiting" materials on their surfaces which serve as food sources for aquatic organisms!

Yeah, I'm talking about the biofilms and fungal growth, which make their appearance on our botanicals, leaves, and wood after a few weeks of submersion...

As we've talked about repeatedly, biofilms are not only typically harmless in aquariums, they are utilized as a supplemental food source by a huge variety of fishes and shrimps in both Nature and the aquarium. They are a rich source of sugars and other nutrients, and could prove to be an interesting addition to a "nursery tank" for raising fry if kept in control. Like, add a bunch of leaves and botanicals, let them do their thing, and allow your fry to graze on them!

Don't believe me?

Ask almost any shrimp keeper-they'll "sing the praises" of biofilm for the "grazing" aspect!

And of course, it's long been known from field studies that as leaves and other plant materials break down, they serve as "fuel" for the growth of biofilm, fungi and microorganisms...which, in turn, provide supplemental food for our fishes. I've seen a bunch of videos of shrimps and fishes in the wild "grazing" over fields of decomposing leaves and the biofilms they foster.

Ahh, biofilms again.


Biofilms form when bacteria adhere to surfaces in some form of watery environment and begin to excrete a slimy, gluelike substance, consisting of sugars and other substances, that can stick to all kinds of materials, such as- well- in our case, botanicals.

Biofilms on decomposing leaves are pretty much the foundation for the food webs in rivers and streams throughout the world. They are of fundamental importance to aquatic life.

It starts with a few bacteria, taking advantage of the abundant and comfy surface area that leaves, seed pods, and even driftwood offer. The "early adapters" put out the "welcome mat" for other bacteria by providing more diverse adhesion sites, such as a matrix of sugars that holds the biofilm together. Since some bacteria species are incapable of attaching to a surface on their own, they often anchor themselves to the matrix or directly to their friends who arrived at the party first.

Sorta sounds like Facebook, huh?

(The above graphic from a scholarly article illustrates just how these guys roll.)

And we know from years of personal experience and observation in the aquarium that fishes and shrimp will consume them directly, removing them from virtually any surface they form on.

And some materials are likely better than others at recruiting and accumulating biofilm growth. The "biofilm-friendly" botanical items seem to fall into several distinct categories: Botanicals with hard, relatively impermeable surfaces,  softer, more ephemeral botanical materials which break down easily, and hard-skinned botanicals with soft interiors, and...

Okay, wait- that kind of covers like, everything, lol.


What that tells ME, the over-caffeinated, perhaps somewhat under-educated armchair "scientist"-wannabe, is that most of the botanicals we offer here at Tannin- in addition to being potentially consumed directly by aquatic organisms- likely also have some capability of recruiting biofilms.

And the idea of biofilms and such being an excellent supplemental food source for shrimp-and fishes- is not revolutionary...it's just something that we're finally getting around to agreeing about with our little friends! (And with the shrimp people, too)

What about fry?

Everyone who breeds fishes has their own style of fry rearing.

Some hobbyists like bare bottom tanks, some prefer densely planted tanks, etc. I'm proposing the idea of rearing young fishes in a botanical-style blackwater aquarium with leaves, some seed pods, and maybe some plants as well. The physically and "functionally" mimic, at least to some extent, the habitats in which many young fishes grow up in.

My thinking is that decomposing leaves will not only provide material for the fishes to feed on and among, they will provide a natural "shelter" for them as well, potentially eliminating or reducing stresses. In nature, many fry which do not receive parental care tend to hide in the leaves or other biocover in their environment, and providing such natural conditions will certainly accommodate this behavior.

Decomposing leaves can stimulate a certain amount of microbial growth, with infusoria and even forms of bacteria becoming potential food sources for fry. I've read a few studies where phototrophic bacteria were added to the diet of larval fishes, producing measurably higher growth rates. Now, I'm not suggesting that your fry will gorge on beneficial bacteria "cultured" in situ in your blackwater nursery and grow exponentially faster.

However, I am suggesting that it might provide some beneficial supplemental nutrition at no cost to you!

I've experimented with the idea of "onboard food culturing" in several aquariums systems over the past few years, which were stocked heavily with leaves, twigs, and other botanical materials for the sole purpose of "culturing" (maybe a better term is "recruiting) biofilms, small crustaceans, etc. via decomposition. I have kept a few species of small characins in these systems with no supplemental feeding whatsoever and have seen these guys as fat and happy as any I have kept.

And it's the same with that beloved aquarium "catch all" of infusoria we just talked about...These organisms are likely to arise whenever plant matter decomposes in water, and in an aquarium with significant leaves and such, there is likely a higher population density  of these ubiquitous organisms available to the young fishes, right?

Now, I'm not fooling myself into believing that a large bed of decomposing leaves and botanicals in your aquarium will satisfy the total nutritional needs of a batch of characins, but it might provide the support for some supplemental feeding! On the other hand, I've been playing with this recently in my "varzea" setup, stocked with a rich "compost" of soil and decomposing leaves, rearing the annual killifish Notholebias minimuswith great success.

It's essentially an "evolved" version of the "jungle tanks" I reared killies in when I was a teen. A different sort of look- and function! The so-called "permanent setup"- in which the adults and fry typically co-exist, with the fry finding food amongst the natural substrate and other materials present I the tank. Or, of course, you could remove the parents after breeding- the choice is yours.

I'd take the concept even a bit further by "seeding" the tank with some Daphnia and perhaps some of the other commonly available live freshwater crustaceans, and letting them do their thing before the fry arrive. This way, you've got sort of the makings a little bit of a "food web" going on- the small crustaceans helping to feed off of some of the available nutrients and lower life forms, and the fish at the top of it all. 

Now, granted, I'm romancing this and perhaps even over-simplifying it a bit. However, I think that there is a compelling case to be made for creating a rearing tank that supports a biologically diverse set of inhabitants for food sources.

The basis of it all would be leaves and some of the botanicals which seem to do a better job at recruiting biofilms- the "harder shelled/surfaced" stuff, like  Jackfruit leaves, Yellow Mangrove leaves, Guava Leaves, Carinaina Pods, Dysoxylum pods, etc...I think these would be interesting items to include in a "nursery tank." And of course, they provide shelter and foraging areas and impart some tannins into the water...the "usual stuff."

It's fun to play with new ideas- or evolve old ones such as this. Maybe this won't be the "ultimate" fry-rearing technique; however, it's just another one of those ideas to have in our "arsenal" of skills that would be fun for serious fish breeder to experiment more with.

I think it's one we have seriously legit basis for playing with more and more!

Nothing is wasted in Nature, right?

To you, my fishy friends, I say, "Let them eat botanicals!" (well, at least as part of their diet, anyways!)- and the materials which accumulate on their surfaces, too!

Let's try not to make too many assumptions, or buy too heavily into vendors' marketing hyperbole- at least, not without doing some of our own research and "field work."

As hobbyists, let's continue to experiment, observe, learn from, and share our experiences and observations with others. 

We all win from that.

In fact, that's likely the one absolute assertion I will make!

Stay curious. Stay disciplined. Stay objective. Stay experimental. Stay creative...

And Stay Wet.


Scott Fellman

Tannin Aquatics 





June 08, 2020



I think I need to clarify something...😆

Let's talk about cloudy water for a second. 

Actually, we've talked about it a lot here, but I think it's something that's going to always come up in our little hobby speciality.

Well, specifically, what causes it?

A lot of things, of course.

Now, many of the causes are biological in nature. In the case of our botanical-style aquariums, the cloudiness could also be caused, at least in part- by the dissolving of the botanicals themselves. When you think about it, most plant parts, such as seed pods and such, are comprised of materials such as lignin, cellulose, etc., and their constituent sugars, starches, etc. And, because of this composition, will release these materials into the water column.

Now, cloudiness, in general, may be a "tip off" to some other issues in the aquarium. And, as we all know, cloudiness can usually be caused by a few factors:

1) Improperly cleaned substrate or decorative materials, such as driftwood, etc. (creating a "haze" of micro-sized dust particles, which float in the water column).

2) Bacterial blooms (typically caused by a heavy bioload in a system not capable of handling it. Ie; a new tank with a filter that is not fully established and a full compliment of livestock).

3) Algae blooms which can both cloud AND color the water (usually caused by excessive nutrients and too much light for a given system).

4) Poor husbandry, which results in heavy decomposition, and more bacterial blooms and biological waste affecting water clarity. This is, of course, a rather urgent matter to be attended to, as there are possible serious consequences to the life in your system.

And, curiously enough, the "remedy" for cloudy water in virtually every situation is similar: Water changes, use of chemical filtration media (activated carbon, etc.), reduced light (in the case of algal blooms), improved husbandry techniques (i.e.; better feeding practices and more frequent maintenance), and, perhaps most important- the passage of time.

Of course, with the "cloudiness" caused by our "technique" or application of botanicals is a slightly different story. These are sort of "natural consequences" of what we do..

Now, you could intervene in this if you wanted to...Performing larger water exchanges, employing chemical/very fine mechanical filtration media, etc. Personally, I have learned over the years NOT to let this stuff phase me. I suppose I'm so deep in my own "mindset" about letting nature do its thing, that I don't do much to combat it...

A lot of botanical-style aquairums start out with a little cloudiness. It's often caused by the aforementioned lignin, as well as by a Burts of microbial life which feeds upon these and other constituents of botanicals.

Once this initial "microbial haze phase" passes, there are other aspects to the water clarity which will continue to emerge. And I think that these aspects are similar to what we observe in Nature.

For example, I've noticed that in many of my aquariums, particularly those with certain types of wood (like mangrove, newer Mopani, etc.), you'll get more of a sort of "patina" to the water. Again, I'm squarely in the realm of speculation here, but I can't help but wonder if certain wood and botanical materials/leaves have a greater content of organic materials (or more readily release these materials into the water because of their structure), lignin, tannins, etc., thus creating this phenomenon?

Those of us in the community of blackwater, botanical-style aquarists seek out tint and "body" in our water...while the rest of the aquatic world- well, they just sort of... freak the fuck out about that, huh?

One of my friends calls this "flavor", and his moniker makes sense, when you think about it!

And I think that this is a really interesting phenomenon, which is distinctive to our botanical-stye blackwater/brackish aquariums. To accept it is a choice, and it definitely requires the adoption of a mindset shift to appreciate that this is very similar to what we see in many of the natural aquatic systems that we attempt to replicate.

When we begin releasing some of our "NatureBase" substrates in the coming months, you'll understand first hand why water clarity isn't as important a factor in creating a "healthy" aquarium as the water quality is.

In Nature, the accumulations of decomposing plant materials, leaves, and sediments all contribute to this cloudiness or turbidity of the water. In our aquariums, it's pretty much the same!

Yes, we are always of the opinion that an aquarium is NOT an open, natural system, and that there are fundamental differences between the two.

However, to see some of the processes, aesthetics, and what we call "functional analogies" (i.e.; the way materials break down, re-distribute within the tank, and how the aesthetics and water chemistry are affected by water exchanges, etc.) take place in our aquariums, we can't help but think that we're "on to something" here.

(Image by Aquariumaniak Khizanishvili- a master of the "dirty" aquarium!)

Nature is simply not a squeaky-clean place. It just isn't.

So, yeah, our aquariums may NOT have the "crystal-clear", colorless water which many hobbyists envision when they think of what an aquarium "should" look like. Yet, with the continued, evolving work which our community is doing, we'll continue to discuss/analyze/debate the merits of such clarity profiles in our systems.

In Nature, we see these types of water characteristics in a variety of habitats. While they may not conform to everyone's idea of "beauty", there really IS an elegance, a compelling vibe, and a function to this. 

Fish don't care that their water is tinted, a bit turbid, and sometimes downright cloudy.

As we've discussed a lot lately, we're absolutely obsessed with the natural processes and aesthetics of decomposing materials and sediments in our aquariums. And of course, this comes with the requirement of us to accept some unique aesthetic characteristics, of course!

It's almost like our idealized aesthetic perceptions of what we feel water should look like in an aquarium have conditioned us as a hobby to sort of gently disregard what it truly looks like in the habitats from which our fishes evolved. Now, I'm certainly not asserting that keeping fishes in a crystal-clear aquarium is somehow going to ruin their vitality or render them susceptible to many illnesses, or that providing "blackwater" conditions is some sort of miracle concept that will lead to unimagined success.

However, I'm at least curious about how much better our animals might do long-term (I'm talking decades in captivity of being bred, etc.) if maintained in conditions that more-or-less replicate the waters from which they evolved. We've seen a lot of Betta and Apistogramma breeders utilize these types of conditions in their aquariums for many years, and their successes have been obvious.

We have taken our first tentative footsteps beyond what has long been accepted and understood in the hobby, and are starting to ask new question, make new observations, and yeah- even a few discoveries- which will evolve the aquarium hobby in the future.

Stay curious. Stay observant. Stay engaged. Stay bold. Stay engaged...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



June 05, 2020


Small creatures. A bigger perspective, and a huge impact!

One of the aspects of botanical-style aquariums that we discuss from time to time, but can't bring up enough, is the importance of the "microbiome" of the aquarium environment.

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

You may not see them- at least, not all of them. However, they are present in almost every aquarium...Especailly our natural, botanical-style aquariums.

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

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

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

Many of us are even moving beyond just the pretty look of the botanical-style aquarium, and moving into a deeper stage of understanding how our aquariums function as miniature ecosystems.

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

I have long been one the belief that if you decide to let the botanicals remain in your aquarium to break down and decompose completely, that you shouldn't change course by suddenly removing the material all at once. 

The point is, our aquariums, much like the wild habitats we strive to replicate, are constantly evolving, accumulating new materials, and creating new physical habitats for fishes to forage among. New food sources and chemical/energy inputs are important to the biological diversity and continuity of the flooded forests and streams of the tropics, and they play a similar role in our aquariums.

We add leaves and botanicals periodically, not just for an aesthetic "refresh", but for a "re-charge" of the biome within our tanks. This is a fascinating spect of the botanical style aquarium. It facilitates the cycle of growth, nutrient accumulation, and decomposition. It becomes not only part of our practice, but it's part of the "system" we are trying to facilitate.

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

And we have to accept nature's input here.

Nature dictates the speed by which this decomposition process occurs. We set the stage for it- but  Nature is in full control.

And that's perfectly okay! 

Nature can control. Nature can stabilize. Nature can admonish us...However, Nature can also provide.

We've talked a lot about allochthonous input- food which comes from outside the aquatic environment- such as insects, fruit, seeds, etc. You know, stuff which literally falls from the trees! However, there is also a significant amount of food which our fishes can obtain which occurs within the aquatic habitat itself. 

This is something that we, as lovers of the botanical-style aquarium, are well-suited to embrace. And of course, I"m utterly fascinated by the concept of food production within our botanical-style aquariums! Yes, food production. If you really observe your tank closely- and I'm sure that you do- you'll see your fishes foraging on the botanicals...picking off something.

I've noticed, during times when I've traveled extensively and haven't been around to feed my fishes, that they're not even slightly slimmer upon my return, despite not being fed for days sometimes... 

What are they eating in my absence?

Well, there are a number of interesting possibilities.

Perhaps most interesting to us blackwater/botanical-style aquarium people are epiphytes. These are organisms which grow on the surface of wood, botanicals, plants or other substrates, and derive their nutrients from the surrounding environment. They are important in the nutrient cycling and uptake in both nature and the aquarium, adding to the biodiversity, and serving as an important food source for many species of fishes.

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

The biocover consists of stuff like algae, biofilms, and fungi. Although most animals use leaves and tree branches for shelter and not directly as a food item, grazing on this epiphytic growth is which occurs on them is very important.

I am of the opinion that a botanical-style aquarium, complete with its decomposing leaves and seed pods, can serve as a sort of "buffet" for many fishes- even those who's primary food sources are known to be things like insects and worms and such. Detritus and the organisms within it can provide an excellent supplemental food source for our fishes!

It's well known that in many habitats, like inundated forests, etc., fishes will adjust their feeding strategies to utilize the available food sources at different times of the year, such as the "dry season", etc. And it's also known that many fish fry feed actively on bacteria and fungi in these habitats...so I suggest one again that a blackwater/botanical-style aquarium could be an excellent sort of "nursery" for many fish and shrimp species! 

And of course, it goes beyond even that...

Because of the very "operating system" of our tanks, which features decomposing leaves, botanicals, soils, roots, etc., we are able to create a remarkably rich and complex population of creatures within them.

This is one of the most interesting aspects of a botanical-style aquarium: We have the opportunity to create an aquatic microcosm which provides not only unique aesthetics- it provides soem supplemental nutritional value for our fishes, and perhaps most important- nutrient processing- a self-generating population of creatures that compliment, indeed, create the biodiversity in our systems on a more-or-less continuous basis.

True "functional aesthetics", indeed!

Another important part of our aquarium microcosms are fungi.

Yeah, you heard me. Fungi.

Fungi reproduce by releasing tiny spores that then germinate on new and hospitable surfaces (ie, pretty much anywhere they damn well please!). These aquatic fungi are involved in the decay of wood and leafy material. And of course, when you submerge terrestrial materials in water, growths of fungi tend to arise.

Anyone who's ever "cured" a piece of aquatic wood of almost any type for your aquarium can attest to this!

Fungi tend to colonize wood because it offers them a lot of surface area to thrive and live out their life cycle. And cellulose, hemicellulose, and lignin- the major components of wood and botanical materials- are degraded by fungi which posses enzymes that can digest these materials! Fungi are regarded by biologists to be the dominant organisms associated with decaying leaves in streams, so this gives you some idea as to why we see them in our aquariums, right?

And of course, fishes and invertebrates which live amongst and feed directly upon the fungi and decomposing leaves and botanicals contribute to the breakdown of these materials as well! Aquatic fungi can break down the leaf matrix and make the energy available to feeding animals in these habitats.

And look at this little gem I found in my research:

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

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

It's easy to get scared by this stuff...and surprisingly, it's even easier to exploit it as a food source for your animals! This is a HUGE point that we can't emphasize enough.

And of course, the same goes for our buddies, the biofilms.

Biofilms are interesting, in and of themselves. Understanding the reasons they arise and how they propagate can really help us to appreciate them!

We've discussed this before; however, let's revisit the process one more time:

It starts with a few bacteria, taking advantage of the abundant and comfy surface area that leaves, seed pods, and even driftwood offer. The "early adapters" put out the "welcome mat" for other bacteria by providing more diverse adhesion sites, such as a matrix of sugars that holds the biofilm together. Since some bacteria species are incapable of attaching to a surface on their own, they often anchor themselves to the matrix or directly to their friends who arrived at the party first.


These bacteria and fungi are all participants in a rather grand process of nutrient utilization- both in Nature, and in our aquariums. And it all starts with adding botanicals and leaves to our systems. This is absolutely analogous to what happens in Nature.

And that is EXACTLY what we want. Not to give Nature "lip service" as many aquarium hobby movements do. No, we want to embrace Nature in all her glory and diversity. We want to replace our expectations of what we think Nature should look and function like, and simply study, understand, appreciate and support her processes in our aquariums

We need to really step back sometimes and separate ourselves from the sexy (well, to some of us) look of botanical-style aquariums, and really try to grasp the biological diversity that occurs in our tanks! We need to celebrate it- regardless of appearance- and understand how amazing this really is! 

The front row seat that we as botanical-style aquarium lovers have is quite unique in the aquarium hobby. In my opinion, no other hobby speciality is poised to study, appreciate, and embrace the vast diversity and process of Nature like we are. It's incredibly exciting and humbling to realize that the mental shifts that our community has taken- going beyond just the aesthetics- and really working with Nature, as opposed to fighting Her- will likely yield some of the most important breakthroughs in the history of the aquarium hobby.

We're glad you're here. We're super proud to be supporters of this new, vital movement to create the ultimate expression of "natural" in our aquairums!

Stay curious. Stay fascinated. Stay diligent. Stay humble. Stay bold. Stay unique...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


June 04, 2020


A good facsimile? The value of analogs.

Often, I'll come up with an idea for the aquarium representation of a unique niche habitat, and will spend a lot of time researching the ecology and, more important to me- the function of  the habitat, before embarking on my project. 

And yeah, more often than not, I'll find that the plants, wood, leaves, or whatever that I need to really nail the project in a a full-on "biotopic manner" are simply not available to me.

And guess what? That's okay. I don't "get stuck." 

I just don't get stressed out about it.

You shouldn't, either.

I receive a lot of emails from fellow hobbyists who are "stuck" because they can't find that exact plant...And so they dramatically change, or even abandon their projects.

A real shame.

A suggestion, if I may?

Look for some sort of analog.

For example, a plant that is found in my region which can inhabit a similar niche. If I'm lucky, the plant even looks similar to the subject I'm trying to represent.

Case in point?

It's not a secret that flooded forests/grasslands are an obsession for me.

For the amount of "ink" I devote to talking about flooded forests and grasslands, you'd think that I'd have some good suggestions about how to plant these tanks, right?

Well, I do!

And of course, I'll share my recommendations with you on these in a minute. However, I also have a suggestion to our community in general about replicating these habitats:

Let's figure out which terrestrial plants can tolerate/grow/thrive under submerged or partially submerged (blackwater) conditions. Perhaps a more "realistic" (not in the hardcore "biotope aquarium contest" context, of course) avenue to explore in this regard?

Well, it starts by studying the wild habitats that we are trying to recreate...

Think about how they form. Think about how plants grow in them during the dry season, and what materials would be found on the forest floor or grasslands when the water is absent.

The forest floors are littered with leaves and seed pods from the overhead forest canopy. With some much material on the forest floor, the potential for a dynamic ecosystem in both the wet and the dry season is assured!

Conceptually, this is absolutely easy to recreate in the aquarium/vivarium, right?

You can create remarkably faithful representations of these environments by simply working backwards...thinking about what the forest floors are like, what lives there, and how materials accumulate. What materials are found...And most important, perhaps- what trees do they come from?

I've got one tree for you to research...the dominant terrestrial plant in the South American flooded forests is Eugenia inundata... Don't think I'm not well underway in my (somewhat futile) efforts to see if we can secure fallen leaves of THIS plant!

Surely, if we can't find specimens of this plant, we can certainly find some similar plants to use in its place? At least, we could utilize wood, roots, or other materials to represent the look of this plant during its "submerged" phase. What would YOU use to represent this plant?

BTW "What would you use...?" is a great excercise for natural-style aquarium lovers who are obsessed with replicating weird habitats...Just sayin'...

And of course, there are many other plants which are found in these habitats, some of which we are likely never to see available; however, we could figure out some analogous species, right? Look at the picture below and get out of your own head space for a moment...

What species DO we find there?

You'll also find Iriartea setigera, Socratea exorrhiza, Mauritiella aculeata palms in these areas, just to name a few. I say, hit Google hard. Learn more about these. Find out what related species you can source.

(Mauritiella aculeata - Image by pixel too used under CC BY 2.0)

Like so many things from the Amazon, it's not easy (read that, damn near impossible) to secure many botanical materials from this region, so the proverbial "Don't hold your breath waiting for this" comes to mind! Oh, and the submerged grasses we see and drool over in those underwater pics from Mike Tucc and Ivan Mikolji of these habitats?

They're typically Paspalum repens and Oryza perennis.


And we DO have access to some species, such as Sedges and other riparian or semi-aquatic/bog plants from genera that are found in these regions, such as Papyrus (Cyperus), Acorus, Orzyas, etc. These are surprisingly popular plants in the hobby, and for the purpose of recreating one of these seasonally-inundated habitats, they're near perfect! 

Since many of these plants tolerate submersion for extended periods of time, they are of great interest to many of us for use in our aquariums. Perhaps most interesting to me is the area below the water, where the roots, fallen leaves, and shoots of plants like Cyperus are found in abundance.

A dramatic and inspiring area to replicate in the aquarium, I'd think. It's one thing to simply plant some in an aquarium- very cool...However, it's quite another to represent part of the ecological niche in which they are found in a unique and different way.

SO, sure, you can keep plants like Acorus in these submerged or partially submerged environments. Part of what interests me is that these are generally very hardy plants.

There are numerous species more commonly available from commercial nurseries in North American and European nations, so creating realistic representations of these habitats in our aquariums is more attainable than ever!

You just need to do a little research.

Now, there are also lots and lots of possibilities for creating unique aquatic displays with what I would call "aquatic analogs" of these terrestrial grasses and shrubs. In other words, incorporating some true aquatics to replicate the "look" of the flooded forests and grasslands, using representative species.

I freely admit that this is a total "cheat"- but when you think about it, it's a pretty good method that can be employed if you want to represent the inundation period for the theme of your aquarium, and aren't able to secure or grow the terrestrial/semi-aquatic analogs to the species found in these habitats.

I'm thinking about plants like Echinodorus tenellus, the "Pygmy Chain Sword", which grows in a most "grasslike" state, and certainly is representative of the grasses one might find on a flooded Panatanal or forest floor habitat in South America.

It's not hard to cultivate a little section of these plants in your representation of a flooded forest, and drop in a few leaves and botanicals, and achieve a relatively realistic-looking facsimile of this unique habitat!

Another great candidate that has a sort of "generic tropical/ terrestrial grasslike" appearance would be Cryptocoryne parva. This diminutive plant actually can be grown emerged, so for "semi-flooded" igapo or varzea biotope aquariums, it would be really adaptable! And when submerged, it bears strong resemblance to Paspalum or other tropical, submersion-resistant grasses. (It's the plant in the foreground in the below pic, BTW)

I suppose the old fave, Sagittaria, could also be employed for this purpose, but some species can achieve a larger size and perhaps ultimately be not as realistic, so you'd need to choose carefully. More exotic, but readily available as tissue-cultured, would be the beautiful Lilaeopsis mauritiana, a species often called "Micro Sword" for its appearance and size.

And of course, since we're representing a flooded forest floor or meadow, with patchy growth over rich soil and leaves, you likely don't need to have the full-on green lawn that planted aquarists strive for so ardently! A little bit of "open space" and some twigs, roots, dried weeds, bark pieces, a few seed pods, and exposed substrate and you're well on your way to creating a remarkably realistic, and undeniably cool tank!

Just plant some of it here and there in such a tank, and....well, yeah, you get the idea, right? 😆

And of course, you can always replicate the look and function of the areas where land and water meet. 

Now, sure, playing with these types of setups bring together hobbyists from a number of disciplines- vivarium/terrarium people, aquarists, planted tank enthusiasts, botanical-style aquarium lovers (that's US!), etc. Each party will have their own unique "take" on this process, as well as accompanying criticisms of the process and management.

However, "putting it all together" is really a fun process!

So, the most important takeaway here is NOT to be "stuck" because you don't have access to the exact plants that you'd fin in these habitats. You can research the ecology of these habitats, and find analogs that capture both the look and function of their wild subjects. 

Appreciate these analogs as functionally aesthetic means to recreate some of the world's most amazing natural ecosystems- during both the "dry" and "wet" seasons...

Stay creative. Stay studious. Stay observant. Stay unflustered. Stay motivated. Stay bold...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


June 03, 2020


Guarantees in the hobby- and dissing the "Aquarium Gods!"- Words to the wise...

If you read my blog and listen to my podcasts, you know my complete disdain for "guaranteeing" anything we do in the hobby to give absolute results. And that goes to stuff we do, as much as the stuff we use in the hobby. 


Yeah, there are some things that we can do as hobbyists which will simply tempt the "Aquarium Gods" ( I am pretty certain that there ARE some!) to pretty much kick your ass...some more than others.

"Examples, Scott?"

Okay... How about this one:

Never move “just a couple of rocks and wood pieces” around in your aquascape within an hour of going to sleep at night- particularly on a week night, or before a morning when you just have to wake up early! Trust me, you won’t be getting restful sleep any time soon. It’s almost a certainty that moving one rock with the intention of “opening up space” or making a minor “tweak”, will lead to you pulling out a dozen rocks, a few driftwood pieces, a plant or two- or even the whole aquascape before the job is done, which could take hours and hours without completion.

I recall, in years past, attempting that one "quick adjustment" before heading out to work for the day, only to find myself deeply involved hours later, calling in sick to work, no closer to resolution- and the room filled with wet towels, lots of pieces of rock and wood all over the floor, and the wet footprints of a very frustrated fish geek! 

In fact, the job may not be done for days!

At some point, after numerous attempts to “correct” things, you’ll throw in the towel, and try to just make things “the way they were” before your started this futile endeavor…And guess what? You’ll NEVER be able to re-create what you had before…total bummer, which will take hours and hours to correct. We know this well- but we still do this.  Just don’t do it, trust me.

Changing light bulbs, settings, or the lighting system before a trip- This one is like the proverbial  “kiss of death!” I mean, really, changing light bulbs is no big deal, right? Oh, trust me, it is, especially when the new bulbs are a different spectrum (like if you use T5’s) ,or if you change up the colors or photoperiod with LED's-  or if you’re changing lighting formats from fluorescent to LED, for example. Not only will your plants likely react a bit differently when you expect- they will undoubtedly demonstrate their apparent displeasure at the worst possible time (like when you are away), and you may come back to a disaster in the making, or worse!

This shit really comes into play when you have a reef tank. Corals HATE adjusting to new lighting formats, spectrums, and photoperiods, and the inevitable meltdowns which occur are excasserbated when you're not around...and the whole aquarium can go into a big, stinky "death spiral!"  Coming home to a tank of dead coral is a sight and smell you definitely won't soon forget! Yeah, it really happens…Don’t ask me why, but it’s nerve-wracking enough just doing such a change when you’re going to be home…but if you’re leaving town...You are absolutely tempting fate! Be ready to replace some plants upon your return…at the very least! Yikes!

And just for my fellow reefers...

Turning the ball valve on your protein skimmer to make a "minor adjustment" to water intake when you’re in a hurry -You’re sooo screwed! I mean, there is no such thing as a “quick adjustment” to a protein skimmer…They’re totally finicky, and a sure ticket to headaches when you’re in a hurry…Or even when you aren’t, right? The same caution applies to making adjustments to your CO2 solenoid or feed valve on a reactor…ridiculously small adjustments are the only way to go…I mean, almost non-existent changes…

Air/water mix ratios, chemical feeds, and other dynamics can just get screwed up so easily it’s not even funny. Subtlety and time are everything with these kinds of changes. If you rush them, have plenty of Tylenol or your favorite pain reliever, wine, or beer available- it’s a virtual certainty that headaches will be waiting for you when you’re done. 

Taking a chance on that "cool cichlid" that was a perfect citizen in your buddy’s tank. -Are you KIDDING ME? SERIOUSLY? NO! NO! NO! It’s a virtual guarantee that the innocuous fish that resided in your buddy’s 400-gallon Malawi “community” tank for 7 years without incident will suddenly develop a great appetite for your precious juvenile Taeniolethrinops macrorhynchus or Mylochromis species. Yeah, your really rare, pricy ones.

I mean, you can practically take it to the bank!  Reefers know that the same goes for the anemone that never moved in your friend’s reef aquarium. Ask yourself, if the animal is such a model citizen, why is he or she getting rid of it? Prepare for knocked-over corals- or worse. Why on earth aquarists even think of tempting fate by trying these sorts of “additions” is beyond me sometimes!

"He seemed SOO nice!" (image by Oosh CC BY-SA 3.0)

Skipping quarantine with that "healthy" new addition- This isn't just superstition talking- it’s firmly grounded in reality..Skipping quarantine with one fish, or one coral, if you're a reefer- can open up your entire system to a limitless number of diseases or other maladies that can create dire consequences for your aquarium. Totally not worth it. We know this, but many of us tempt fate anyways. Some even get cocky and BRAG about it! And as we all know, bragging about shit like this a guarantee that the Universe- and those pesky "Aquarium Gods"- will even the score with you at some point.

Quarantine is a vital, logical practice that is employed by every public aquarium on the planet, and scores of successful hobbyists everywhere. You definitely are playing “Russian Roulette” with your aquarium if you skip this practice. Even if you know the source, have observed the fish repeatedly at the store or in its prior owners’ aquarium, it’s not worth it. Trust me.

Totally not worth it.

Going to a club auction with the intention of just “checking stuff out”- Pu-leeeze! Seriously? You have just about guaranteed that you’re going to leave with fry of something. In fact, you’ll probably leave with fry of several “somethings”. Auctions and "frag swaps" are irresistible to aquarium geeks, and the generosity of hobbyists is well documented.

“Oh, you’re a newbie? Here- have a frag of this Xenia, and some fry of these Nothobranchius guentheri…Super easy to keep…Can’t lose!” Even if you didn’t bring money, you’ll likely leave with way more than you intended. I have seen numerous times where aquarists even ended up borrowing from their teenage kid to grab a fish (because he was determined not to tempt him/herself by bringing cash to the event). So my advice if you’re attending a club auction? Just bring cash. That little group of Boraras? You'll find space in your fish room for them...somewhere! Seriously.

Bring a cooler. Leave restraint at home.

Okay, so there is just a quick rundown of “sure things” in the aquarium hobby. I mean, there aren’t that many certainties in this game, are there? Well, actually, there are. Sure, I focused on a few with some potentially bad consequences…There are no doubt countless others with the possibility of better outcomes…but it’s far more fun to highlight the bad ones, isn’t it? LOL

Oaky- that's a quick rundown of  some of my personal "guarantees"-based on decades of experience and learning-finally- not to tempt the "Aquarium Gods!" 

So, let’s hear your “guarantees” in the aquarium hobby!

I know that you’ve got way many more examples of this that you can add to our “database!"

So, go ahead- tempt fate...but don't say that I didn't warn ya!

Stay bold. Stay thoughtful. Stay diligent. Stay careful!

And Stay Wet.


Scott Fellman

Tannin Aquatics

June 01, 2020


To the roots...

I spend a tremendous amount of time focusing on specific habitats and ideas to recreate them in the aquarium, and few have proven as popular- or alluring- as the flooded forest floors of Amazonia. We've visited these habitats multiple times in our blog, and done some discussion on the fishes and animals which reside in them during the periods of inundation (which is usually around September to the end of May).

When the forests flood, the sandy soils are carpeted in aggregations of botanical detritus, root tangles, fallen logs, leaves, bark, etc. from the formerly dry forest floor. This is, of course, the stuff we as botanical-style blackwater aquarium enthusiasts are most interested in. One of the key components of this habitat, from a "structural/spatial" sense, is the presence of logs, branches, and roots from fallen trees.

Yes, roots.

We see many aquariums which feature wood and leaves, of course. However, I think we don't see a tremendous use of smaller branches, roots,  and "twig-sized" pieces, and I think that is something we would definitely like to see more of in our aquariums. There is something remarkably realistic about the presence of these smaller materials in an aquarium. The complexity and additional "microhabitats" they create are compelling and interesting. And they are very useful for shelling baby fishes, breeding Apistogramma, Poecilocharaxcatfishes, Dicosssus, an other small, shy fishes which are common in these habitats. 

Now, small root bundles and twigs are not traditionally items you can find at the local fish store or online. I mean, you can, but there hasn't been a huge amount of demand for them in the aquascaping world lately...although my 'scape scene contacts tell me that twigs are becoming more and more popular with serious aquascapers for "detailed work"...so this bodes well for those of us with less artistic, more functional intentions!

In flooded forests, roots are generally found in the very top layers of the soil, where the most minerals are. In fact, in some areas, studies indicated that as much as 99% of the root mass in these habitats was in the top 20cm of substrate! Low nutrient availability in the Amazonian forests is partially the reason for this. So, ecological reasons aside, what are some things we as hobbyists can take away from this? 

Well, for one thing, you can use a lot of materials to create a very dense look of tangled root structures extending into the water. For example, Melastoma roots have a perfect, delicate structure, and when combined with smaller wood pieces of materials like "Spider Wood", "Tangle Wood Root", or even "Tiger Wood" from our collection, create a very unique, realistic look.

Although we are out of Melastoma roots at the moment, we are expecting a large, long-delayed shipment (Thanks, coronavirus) of them later this month! The nice thing about a tangled mix of roots is that it not only creates a unique aesthetic- it creates a fascinating natural foraging area for fishes.

Okay, "infomercial" time over.

Fungal growth, biofilms, and small crustaceans/microorganisms will live in the tangled matrix of small roots with enormous surface area. This has the dual advantage of functioning not only as a producer of supplemental food sources, but as a natural nutrient processing "facility" in the aquarium. This is a huge and important benefit provided by this type of assemblage.

In Nature, these assemblages also serve a similar role, and "sequester" materials like leaves and such, further adding value to the resident life forms. These areas are ideal for fishes to use for spawning sites and shelter from predators, as well.

The trees-or their parts- literally bring new life to the waters which surround them.

The materials that comprise the tree are known in ecology as "allochthonous material"-  something imported into an ecosystem from outside of it.  (extra points if you can pronounce the word on the first try...) And of course, in the case of trees, this also includes includes leaves, fruits and seed pods that fall or are washed into the water along with the branches and trunks that topple into the stream.  

These materials are known to ecologists as “coarse particulate organic matter”, and in the waters of these inundated forest floors there is a lot of CPOM, and the community of aquatic organisms (typically the aforementioned aquatic insects and crustaceans) has a high proportion of “shredders”, which feed on the CPOM and break it up into tinier bits called (wait for it...) "fine particulate organic matter."

Some of these "shredders" and their larvae are a direct source of food for fishes, providing a nutritious food source for growing populations in these waters.

And of course, some fishes directly consume fallen fruits and seeds themselves as part of their diet as well, aiding in the "refinement" of the CPOM.  Think about the Pacu, for example, which has specialized mouthparts suited to crushing hard-shelled fruits and seeds. Other organisms make use of the fine particulate matter by filtering it from the water or accessing it in the sediments that result. These allochthonous materials support a diverse food chain that's almost entirely based on our old friend, detritus!

Yes, detritus. Sworn enemy of the traditional aquarium hobby...misunderstood bearer of life to the aquatic habitat. Just another benefit (yeah, you heard me right) to recreate these complex "root tangles" in the aquarium.

I have this obsession with these little niches in wild habitats, where a confluence of materials occurs. There IS something fascinating about tangled roots, branches, submerged, decaying vegetation, and rich substrate intersecting in the wild that has inspired me to replicate aspects of them in my aquariums in recent years. 

We talk a lot about "microhabitats" in Nature; little areas of tropical habitats where unique physical, environmental and biological characteristics converge based on a set of factors found in the locale. Factors which determine not only how they look, but how they function, as well.

As aquarists, observing, studying, and understanding the specifics of microhabitats is a fascinating and compelling part of the hobby, because it can give us inspiration to replicate the form and function of them in our tanks! Just looking closely at an image of one of these locales can give you a plethora of tank ideas! 

Continue to look to Nature for your inspiration. Make the effort study the way life forms adapt to these habitats and live within it. The lessons we can learn are so numerous, and so potentially beneficial, that we simply can't overlook this niche.

Get back to the roots! Literally!

Stay bold. Stay curious. Stay creative. Stay excited. Stay observant...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


May 29, 2020


Going big..Well, bigger, at least!

Ladies and gentlemen, welcome to the confusing, chaotic place that is my mind...

Seatbelts, please...

Have you ever had a little tank you liked so much that you wanted to duplicate it in a scaled up size? Well, that's me right now.

We've talked many times about the idea of using so-called "nano aquariums" as a sort of "testbed" for ideas and concepts. The idea that it's easier to try some of these exotic experiments on a small scale than it is to go right to the "big time" is top of mind.

I've totally embraced this, after a long and storied hatred of nano-sized aquariums...I've found that they actually give me a lot of flexibility, and the capability of trying out new concepts easily and quickly.

As many of you know, I have been testing my concept of what I have been calling the "Tucano Tangle"- a 9-gallon aquarium set up to replicate aspects of the habitat of the Tucanoichthys tucano, a characin found only in one area, the Rio Uaupes- specifically, "a brook emptying into the igarape Yavuari"...like, that's pretty damn specific, right?

Damn, those sluggish streams and flooded forest floors again...

And of course, with me essentially trashing the idea of a hardcore, 100% accurate replication of such a specific locale, the idea was essentially to mimic the appearance and function of such an igarape habitat, replete with lots of roots and leaf litter.

This is what I came up with.

And man, I love this tank. It's been a lot of fun.

Like, I love it more than any other "biotope-inspired" tank I've ever set up.  I tried it on a small scale because of the tiny size (and breath-taking price) of the Tucanos; I figured they'd be utterly lost in a larger (like 50 US gallons) aquarium. Not to mention, that I'd have to take out a second mortgage on my home to acquire a population significant enough to make it look like there were any fish in the tank! 

Yet, here I am. 

Of course, I enjoy the small tank and have no plans to take it down any time soon. However, I love the physical appearance and the function of the aquarium so much that I totally want to scale this baby up! That's a total fist-geek mindset, for sure. Now, the idea of populating said tank entirely with the little Tucanos- although tempting, is sort of an economically impractical approach. I suppose I could do that...but at $12USD each, to get a school justifiably large enough to place in a 50-gallon tank would be pretty pricy.

And of course, some other fishes are found symmetrically with the Tucanos- specifically, the cute little cichlid, Ivanacara adoketa, some Amblydoras catfishes, Rivulus (yeah, killies- but the fucking things jump like mad...and in my open-top tank...), and the coolest of all- the equally tiny, elusive, and somewhat pricy Poecilocharax weitzmani- a fish that looks a lot like the Tucanos, but dwells in the leaf litter!  

Oh, man.

How can I resist doing this?

I don't know if I can for much longer, lol.

So, picture a scaled-up version of the little tank...The main thing I'd do differently would be to slope up the substrate towards the rear of the tank, and really make sure that the Melastoma roots or Tangle Branch Wood that I use are placed more towards the rear, giving the impression of a bunch of roots from marginal vegetation (species of Ficus and Leopoldina species are the dominant jungle plants in the habitat I'm interested in replicating). Perhaps, I'll arrange them in a bit of an arc, which will provide a lot of "front and center" swimming area- and a "basin" of sorts for leaf litter to accumulate.

The scale of a larger tank will allow me to create the more open, yet still complex  'scape that I am envisioning here. 

Oh, now I'm liking this idea even more now. I can fully visualize this.

So, my little exercise in scaling up will cost me a lot of money, a little bit of enjoyable time, and provide unlimited awesomeness...

I think.

Yeah, it will.

Right? Maybe? Yeah.

Damn it. Stop me.

Or maybe not...enable me, then. Yeah! 


That's what's my head this morning. I want to do this...at least right now I do...

Thanks for dropping in...

Stay creative. Stay innovative. Stay restless. Stay bold. Stay diligent. Stay motivated. Stay a little...wierd...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




May 28, 2020


Stocking "in sequence?" An approach to creating more natural aquariums...

The idea of an "aquarium as a microcosm" is not exactly a new concept. However, the idea of setting up an aquarium to provide more than just a physical "shelter" for its inhabitants; but rather, as a functional habitat designed to create a small ecosystem, and an "in situ" food culturing system intrigues me.

And it kind of goes back to looking at natural aquatic systems.

If you're like me, you 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 have a rather keen interest in the way Nature operates in the wild aquatic systems of the world.

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.

In the case of many blackwater, leaf-litter habitats in South America, for example, the whole food web starts with our old friends, fungi and bacteria. In fact, it's been postulated by scientists that the food web depends primarily on the litter and its associated decomposing fungi. From there, sponges, rotifers, and amoeba arise, and are in turn fed upon by "specialist feeders", such as shrimps (yeah, there ARE shrimps in Amazonia!) and detritivorous fishes.

Then, of course, you also have inesect larvae, particularly chrinomods (i.e.; bloodworms- larval "flies"), and small crustaceans such as Daphnia and the like, which are preyed upon by a host of fishes.

And of course, flooded forest areas are also attractive to fishes which consume the very fruits, plant parts, and terrestrial insects- "allochthonous inputs" -materials imported into an ecosystem from outside of it.  As more materials fall from the trees and surrounding dry areas, the greater the abundance of fishes and other aquatic animals which utilize them is found.

These materials will continue to fall into the water and accumulate throughout the period of inundation, maintaining the richness of the habitat as others decompose or are acted on by the organisms residing in the water. And of course, these materials continue to provide foraging for fishes for the duration of this period of time.

So, how does this relate to stocking an aquarium? Is this something we can interpret and utilize in our aquarium designs?

Well, for one thing, 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 the aforementioned allochthonous input...food from the terrestrial environment. This is a compelling way to stock an aquarium, I think. Especially aquarium systems like ours which make use of these materials en masse.

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

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

Now, a lot of smaller, more "aquarium suited" fishes will also pick at these fruits and seeds, so you're not totally stuck with the big brutes! 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! 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 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?

In other words- are they more "comfortable" because of some long-established internal "programming", which provides them with a certain degree of "well-being", if you will, knowing that minimal competition or predators are about? Do they behave differently, acclimate to captivity faster...feed better, have more robust overall health and resistance to disease? 

Do these conditions help initiate spawning behavior more readily? 

Interesting to ponder, huh?

These are purely speculative, but they can give you some examples of things that we could unlock when we think about how the natural habitats become populated following seasonal and other environmental changes and evolutions. Studying these changes and the conditions which create them is a fascinating educational process that we should all embrace!

The idea of "meeting your tank where it is" and working to stock it and manage it based on what phase of its existence in is fascinating to me. Now, it's not new to add fishes in a sequence or whatever...yet I believe it IS an evolution in the process when we look at stocking in the context of how the environment we're trying to replicate evolves and hosts fishes.

It's sort of another way of looking at many aspects of our aquaria differently- such as providing environmental parameters appropriate for the fishes we like, to aquascaping based on the physical needs of the fishes and the environmental niches from which they come. Not simply "aquascaping" an aquarium, then adding the fishes to compliment it.

I'm thinking about looking at a natural habitat and asking yourself to consider why it looks the way it does, and why the specific fishes which reside there are present. Asking yourself what makes them live there?

How fishes "follow the food" is just one example of this process.

There are, of course, other reasons besides food. There may be environmental reasons. Adaptations to tidal influxes (I'm thinking of brackish habitats), the need to seek out specific conditions in which to spawn. Freedom from predators...particularly for juvenile fishes.

Of course, I'm thinking about mangrove estuaries and seagrass beds, where many larval fishes go to feed and grow before heading out to sea or other habitats...but there are numerous other examples in various niches...

So many possibilities. There are so many ways to develop aquariums and stock them based simply on looking at Nature.

Meet your aquarium where it is.

Set the stage for the life forms you want to keep by considering exactly what brings them there in Nature...then observe, enjoy, and learn.

Stay observant. Stay inspired. Stay curious. Stay intrigued. Stay objective. Stay patient...

And Stay Wet.


Scott Fellman

Tannin Aquatics