April 27, 2019

1 comment

Scaling up...the internal struggle

Welcome to the confusing, chaotic place that is my mind...

Seatbelts, please...

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 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 flooded forest floors again...

And of course, with me essentially trashing the idea of a hardcore 100% 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.

And man, I love this tank.

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

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 Senggani roots 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 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, 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. Thanks for dropping in...

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

And Stay Wet.


Scott Fellman

Tannin Aquatics 




April 26, 2019


A reasonable "facsimile?"

I'm very happy to see that one of the most popular segments of what we do is to create "biotope-inspired" aquariums- that is, aquariums which have been set up to replicate, on some levels, a specific natural habitat. 

Of course, "on some levels" is the key here. We're not talking exact biotope aquarium, where every fish, twig, leaf, etc. supposedly needs to be spot on for the locale in order to avoid a sound thrashing by the "experts" who lurk on social media. 


We're talking about creating aquariums that are inspired by specific ecological niches, geographic locales, and habitats, which utilize materials that offer a representation, rather than an exact copy, of those found in the stated area. The reality, as we've beaten the shit out of repeatedly here, is that creating an exact duplicate of virtually any biotope is almost impossible, because you'd need to source and utilize the exact soils, botanicals, leaves, etc. found in your target niche.

The irony here is that the fishes are actually the easiest part of the equation! It's the "other stuff" that is more difficult to match up. And I suppose that it makes sense. That's why research is so important. And taking the time to look at the natural habitats...

And the criticisms you might face when you talk with some of the hardcore "biotope elitists?"

I wonder- can these armchair critics really discern the decomposing leaf of Hevea brasiliensis, Swietenia macrophylla, or Euterpe precatoria from Catappa, Guava, Jackfruit, Apple, Oak, etc? I mean, seriously? And, if someone cannot source these specific Amazonian leaves, does that invalidate the aquarium from consideration as a "biotope aquarium?"

No, they likely can't.

Does it even matter?

Whew, I AM getting worked up here, lol.

Again, it's the self-righteous attitudes surrounding these kinds of things that drive me crazy...

The point of my rant is that I think we all want the same thing. We all want to represent. as accurately and faithfully as possible, the biopic niches we're into. And that is incredibly cool! But when we get caught up in semantics and petty arguments for the sake of...well, for the sake of "being right"- who does this help?

Who does it hurt?

Doesn't this kind of criticism hurt those who are in a unique position to use their aquarium hobby talents to maybe, MAYBE reach a few non-hobbyists with their beautiful tank...perhaps raising awareness of the plight of that Borneo peat swamp or African flood plain? Does it discourage them from trying again in the future and sharing their work with the world?

Yeah. I think it does. And that sucks.

We need to lose the attitude on this topic.

I think many aquariums can be accurately labeled "biotope-inspired" or "biotope-style" aquarium. I think a lot of the cool work our community does is at that level.

There is nothing wrong with that at all.

And yeah, my orientation- my personal passion- the passion which led me to found Tannin Aquatics- was to curate, love, and offer my fellow hobbyists the natural materials they can use to create inspiring and compelling natural-style aquariums. To what level of authenticity we all aspire to is the choice of each one of us as individuals.


Now, the problem is, you "can't always get what you want."

It's a reality of the world in which we operate. 

Much as I'd love to offer the leaves of the Hevea basiliensis or whatever, some materials aren't always-or ever- available. One could even make the argument that collecting some items would damage the very habitats that they come from. Some governments forbid or severely restrict the export of certain botanical materials- even fallen, dried leaves and seed pods.

Many of the materials we source are only available because they are a bi-product of agriculture or other domestic activities-many of which are (fortunately), sustainable and eco-sensitive. For example, many of our leaves and pods are from family farms or plantations, which grow fruit or utilize the leaves or seed pods for other purposes as well. That's a lucky thing. 

At the end of the day, I think that everyone can and should put aside their interpretive differences and come to an agreement that just about any aquarium intended to replicate- on some level- a specific wild habitat, ecological niche, or area where a certain fish or fishes are found- is hugely important. Why? Because it calls attention to the habitats and environments themselves. It creates a starting point for discussion, research, debate...It raises awareness of the challenges that many habitats face with the encroachment of man's activities. It most certainly makes us appreciate the fragility of life- the genius of nature, and the incredible diversity and beauty of our home planet.

Even the most poorly executed (by "contest" standards", anyways) "biotope" aquarium helps the uninitiated public (or even the hobby community, for that matter) to become just a tad more enlightened about nature. It might just stimulate someone, somewhere to ask themselves, "Is that what it's like in The Atabapo?" And maybe, just maybe, they'll open up the iPad and do a little reading on the habitat that was being discussed...Maybe they'll take a crack at creating a representation of this habitat themselves. Maybe they will research and find and donate to an organization out there that is working to protect it. 

Call your aquarium a "reasonable facsimile" of a wild habitat. Call it "biotope-inspired." Call it what you want...

It's all good, IMHO. 

Stay inspired. Stay curious. Stay diligent. Stay creative. Stay brave...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


April 25, 2019


On "mindset shifts..."

I'm fascinated by the attitudes we develop in the hobby. By what is popular, unpopular, trendy, disliked, and considered off-limits. Stuff changes over time, but in the short run, it often seems like nothing changes...

Yet, if you've been in the hobby long enough, you start noticing how things truly evolve over the years, and how easily we get comfortable doing stuff that, less than a decade before was considered "risky", "non-sustainable", or downright dangerous.

I think so much of it starts with making mindset shifts and appreciating the challenges associated with doing stuff slightly different than we have in the past. In other words- simply trying. It seems like there is a certain audacity to doing stuff fundamentally differently than we have in the past; call it what you will- but it's that simple. 

It's like someone has to be first...to take the chances; to endure criticisms. To prove that yes- this can be done...and maintained for extended periods of time.

I was chatting with a fellow hobbyist the other day, and we were sort of looking where we are as a hobby, and how our little speciality niche has really caught the eye of more and more so-called "mainstream" adherents in the aquarium hobby. And more important- how more and more hobbyists are letting go of ways of thinking which have helped maintain a certain "status quo" and fear of straying off the well-trodden path for far too long, in my opinion.

As you realize by now, for years, playing with blackwater, lower pH, and decomposing botanical materials was considered an extremely risky, irresponsible, and non-long-term-viable approach to keeping aquariums by many hobby pundits. It still is, in many corners...A fair number of hobbyists still consider this a novelty and a "stunt", if you will, as opposed to a bonafide approach.

And yet, more and more hobbyists are playing with this concept, learning, benefitting, and enjoying.  We are sharing long-term, replicable successes. The reality is that many hobbyists were playing with this stuff for years, it's just that we were quietly experimenting with this stuff in the dark corners of our fish rooms.

Now, we're collectively getting just a bit louder...

Blackwater/botanical-style aquariums have moved out of the "side show" category and are now simply another way to maintain an aquarium. Thanks to the work, experimentation, and sharing of this community, what was once feared is now compelling to many. We still have a long way to go. And quite honestly, a lot of people simply don't like the look. I understand that.  

And I am convinced that this "genre" of aquarium-keeping will always be as much of an "art" as it is a "science"- and that's okay, too. We're literally developing the framework for creating, operating, and managing botanical-style blackwater/brackish systems as we speak. 

Call it "open-source", "ground-floor," "bleeding edge"- whatever you label it, the opportunity for a wide variety of interested hobbyists at all levels to contribute to a body of work has never been better! I think we'll see more and more commercial developments in this area as time goes by, too. Doors have been opened, as they say.

As a hobby, we are becoming more and more progressive, I think. Sure, there are lots of little pockets of resistance to change, holding on to set ways, interpretations, and styles, but you're seeing more and more individual hobbyists breaking away from the "groupthink" and simply doing stuff.

Looking at things from a fresh perspective, experimenting...and generally not giving a damn about what "everyone" thinks...

Scary, daring- yet empowering.

Trying things that are on our minds-scary though they might be...It's how breakthroughs arise in the hobby. It's how we've gotten this stuff out of the "novelty" zone.

Now, I'm not trying to say that our community alone is awesome, and that everyone else is some kind of throwback loser...Absolutely not.  And we're not the only arena in the hobby that's pushing things in different directions. What I AM saying is that we are a good example of a small community of people who have demonstrated how far you can come- and how quickly- when you simply...do stuff. This can work-has worked- in a number of aquarium hobby specialties, from cichlid breeding to Rainbowfish keeping, to aquatic plants and aquascaping. 

It simply requires a different attitude.

A mindset shift.

Mindset shifts are beautiful things, because they get us out of our comfort zones and compel us to look at where we were, where we are, how we got there, and where we are going next.

The "next" part is fascinating to me. Building upon where we've already been, and moving ahead to uncharted waters, so to speak.

Yeah, it's neat to look back- but far more interesting to look forward.

Where to next?

Stay daring. Stay diligent. Stay open-minded. Stay creative. Stay forward-thinking...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


April 24, 2019


Over time...

As you know, I spend a lot of time talking very critically about the short term mindset that seems to be pervasive in the hobby, seemingly enabled by the frenetic pace of tank "do-overs" in the aquascaping world. I sometimes worry if the art of long-term maintenance- or even the idea of keeping an aquarium set up over the long term- like- years versus, ya know- a few months (or a "contest period!")- is a reality that most newer hobbyists have thought of.

Yeah, it's a long game.

In our game, we talk a lot about establishing more natural-functioning/appearing systems, and many of the nuances associated with getting them up and running. However, we seem to spend a relatively small amount of time talking about what actually happens in these tanks over the very long term and how to manage them, right? With so many hobbyists getting  into this style of aquarium for the first time, it's worth another look!

There are some characteristics of these types of tanks which require a fair amount of continued management that keep them functioning as blackwater tanks; most notably, the continuous addition of more botanical items to replace those which break down, be they leaves, wood, or seed pods and the like- in order to maintain not only the visual "tint", but the beneficial humic substances and other organics contained in these materials. 

Over time, many of these compounds are dissolved into the water column, and these botanical materials will no doubt lose some of their efficacy as "environmental enhancers."

And obviously, this sort of "active management" not only creates a more stable environment for your fishes, it provides an opportunity to continuously engage with your aquatic environment on a very regular basis. Continuously replacing and adding more botanical materials over time  is one of the most important aspects of managing this type of aquarium, and is especially critical in an environment in which the very structure of the aquascape itself evolves and changes over time!

Now, unlike other tanks I've managed over the years, such as reef aquariums, planted tanks, etc., where you need to sort of change or evolve your husbandry tasks as the tank ages (i.e.; pruning, revising fertilization schemes, etc.), the botanical-style natural aquarium seems to benefit from the same types of maintenance tasks throughout its functional lifetime.

Some hobbyists choose to let their botanical items remain in the system until fully decomposed; others prefer to remove items just as soon as they lose the "pristine show look." Regardless of how you handle the "botanical breakdown", you're more-or-less following the same practices over a long term. 

Consistency. Our old friend.

And of course, water exchanges are as important a part of the management of our systems as any other. The dissolution of organics and "reset" that water exchanges provide are one of the "cornerstone" practices in aquarium husbandry, and will help continuously hold your environmental parameters. 

As any aquarium ages, it's essential to at least have a handle on what is happening chemically. In the botanical-style, natural aquarium, it's nice to conduct basic water parameter tests early on in the tank's existence, to establish a reference "baseline" of the tanks typical "operating parameters".

In a typical tank, you may see a gradual reduction in pH over time.  This may be caused by acids forming from accumulated nitrate and other nitrogenous compounds and over time, as they overwhelm the buffering capacity of the tank. This seems to be much more common in higher pH systems, such as African cichlid tanks, reef aquaria, etc.

You will likely find, as I have, that with the consistent management of your natural-style blackwater aquariums, very little in the way of "parameter shift" appears to occur. I've seldom noticed any sort of appreciable pH decline over time in these tanks (probably because you're starting out with lower pH!), and nitrate and/or phosphate levels tend not to vary significantly at all with consistent botanical replacements and water exchanges.

I'm curious what YOUR experience has been in this respect.

I also tend to monitor TDS a lot in botanical tanks, and I've found that I will see a "range" of 2-3 ppm at the most, in which the parameters seem to stay throughout the lifetime of the tank. Any deviation from this should be something that you should investigate. Not necessarily a "bad" thing, as TDS can be just about anything...yet it does function as a sort of "yardstick" for environmental consistency.

Ah..consistency over time again.

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

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

Nothing we've mentioned here is earth-shattering or revolutionary, from an aquarium husbandry standpoint. However, seeing that for many hobbyists, this is their first experience at managing a botanical-style blackwater aquarium, and with tons of information out there stressing concepts like breaking down a tank after a few months, I think it's not a bad idea to review this sort of stuff from time to time!

In natural-style aquariums, seldom are big moves or corrections required. Rather, it's really a combination of little things, done consistently over time, which will see your aquarium thrive in the long run. 

Yeah, over time.

Stay consistent. Stay observant. Stay engaged.. Stay involved...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

April 23, 2019


"That pH thing...again."

Oh, it's back to the pH thing, and how botanicals affect it again?

Yeah, it is...

Well, I think we need to talk about it, because we receive so many questions about this topic and there seems to be a lot of misunderstanding about it.

The reality is that botanicals CAN influence the pH of your water...under certain circumstances. 

Simply adding catappa or other leaves to your hard, alkaline tap water will have little to no effect, other than to impart some color and maybe increase your TDS a bit.

I'm starting with RO/DI water, with essentially no carbonate hardness and a very "flexible" pH. Not only do the botanicals influence the color, but they can influence the pH under these circumstances by virtue of the humic acids they can impart to the water. 

However, the tannins, which are the substances which "tint" the water, cannot "overcome" the calcium and magnesium ions, and drive down the pH significantly in water with high levels of these ions present. It simply is putting more materials into the water (which are often detectible by TDS meters in aquariums).

Remember, there are multiple factors in play, and multiple goals you might have for adding leaves to your tank. If it's just about the aesthetics of having leaves in the tank, and you want clear water, use activated carbon in your filter and call it a day!

If you're all about a deeply tinted and low pH environment, you need to eliminate activated carbon in large quantities, employ RO/DI water, and likely use quite a bit more of these materials than I am talking about here.

You have to experiment.

There is simply no "recipe" out there that can give you "Instant Amazon" conditions by adding "a little of this and a bit of that" to your tank, despite what "experts" or vendors will tell you. There just isn't. Period. 

I could talk until "the cows come home" about how much of "this and that" I use in my tank- but I may have a combination of factors that are vastly different from the environment in your aquarium. Sure, you can get some inspiration and a general idea- but your results will vary.  Every tank is different. I think it's more about understanding the general "practices" involved and their impact, versus simply learning "how many" of "whatever" to add.

Until we as a hobby community back off from looking for some specific "recipe" on how to achieve "x" water parameters without exception, and look at each aquarium as a sort of "one off" situation requiring a custom solution, confusion and misinformation will continue to proliferate.

Sure, I can give you my "blackwater recipe", but it's just that: My blackwater recipe.  It works for me:

In one of my display tanks in my home, I use a mix of Yellow Mangrove and Texas Live Oak, with a bunch of Red Mangrove Bark and Oak twigs to achieve a nice color that I like.  (notice I talked about the color in the context of the materials I use?). Now, I also have a pH of around 6.5 and undetectable carbonate hardness; a TDS of around 6 (interesting....).

But that's me. 

I like it. And my fishes like it. My tank runs in a manner that works for me and my fishes. It's not trying to replicate a 4.8 pH Amazonian stream or whatever. It's about creating and managing an environment which I can easily and effectively maintain.

Oh, and the idea of utilizing chemical filtration in blackwater tanks...

Now, I've already touched on the issue of chemical filtration and its impact on removing the tint and tannins associated with leaves and botanicals a number of times in "The Tint" over the years.

Yes, it's entirely possible to minimize or render the ph-lowering and water-tinting capability of tannins released by leaves with activated carbon, Purigen, or other chemical filtration media. Tannins are rather weak acids, yet they can lower the pH of water when their is less "buffer" in the system (i.e.; lower general hardness). Just how much tannins can lower pH in a given system depends upon how much buffering capacity the water has. 

With "harder" water (i.e., water with a greater buffering capacity), you can have the tinted water look from leaves and wood, without the pH reducing effects, particularly if the acids are absorbed by the aforementioned chemical filtration media. So, in other words, you can have the aesthetics of blackwater while running your aquarium at a higher pH if the hardness is sufficient. Once you remove tannins in a lower hardness system, your pH should rise, too, since you're removing the acids.

Woah. Head spin time. 

Bottom line is this: You can use chemical filtration media in "tinted" tanks. However, depending upon the amount of media, quantity of tannin-producing items (leaves, wood, botanicals, etc.) and the capacity of the aquarium, the impact will be variable.

I run chemical filtration media (Purigen and activated carbon) in my tanks, and I still have nice tint and pH relatively stable, as mentioned above. It's a fine line between "too much" and "too little", and you will simply have to experiment to find what works best for you! Nuance and testing guide you.

And never let yourself be fooled. It's a fact:

Botanicals and leaves will NOT soften your water.

I think it's perhaps the most misunderstood thing of all about botanicals in our aquariums. And, I suppose it's easy to see how this one got started and tends to hang around a bit:  (Yes, redundancy tie. again!) Most botanical materials contain tannins and humic substances, which can drive down the pH in water with little to no carbonate hardness.  

And of course, the tinted, soft acidic water in many natural habitats often has an abundance of leaves and botanicals present. I think that this gave a lot of hobbyists the impression that you could simply add some of these materials (leaves, etc.) into your tap water and create "Rio Negro-like" conditions easily! Many are convinced that the "look and color" are indicative of the chemical composition of the water...a misleading and erroneous assumption, as we've discussed repeatedly.

Remember, this can only be accomplished in the aquarium by utilizing source water which has been treated via reverse osmosis or ion exchange ( a process in which calcium and magnesium ions are "exchanged" for sodium or potassium ions.)

Reverse osmosis is a water treatment process which relies on a membrane which has pores large enough to admit water molecules, yet "hardness ions" such as Ca2+ and Mg2+ remain behind and are flushed away by excess water. The resulting product water is thus called "soft water"-free of hardness ions without any other ions being added. 

Want to easily create soft, acid water? Get an RO/DI unit and be done with it...

I attribute my aquariums' relatively stable soft, mildly acidic conditions to the use of reverse osmosis/deionization (RO/DI) to pre-treat my tap water. Yes, RO/DI units are a bit pricy at first. However, IMHO, they are an essential piece of aquarium equipment and a very wise long-term investment for the serious natural aquarium hobbyist!

Yes, this article may simply make your head spin just a bit more, and I apologize if it does...

However, the real aim was to help clear up a few assumptions about creating the type of water conditions in our aquariums which replicate, on some level, some of those from the natural habitats from which our fishes come. Maybe, to get you looking at more of the facts and science behind this stuff, rather than simply searching for a product or "recipe" on how to do things.

I hope that we've helped just a bit!

Stay curious. Stay studious. Stay open-minded. Stay resourceful. Stay diligent...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


April 22, 2019


The "community aquarium" evolution...


 As a dedicated "natural style" aquarium enthusiast,  you entertain lots of unique ideas. And one of the things I've played with a lot in recent years is the art of "nuance" in our tanks...

In other words, going deeper than just the superficial or "big picture" of aquarium configuration. I like the idea of creating "niche micro-habitats" within our aquariums; locales based around a specific feature within the system, which add an entirely new set of physical parameters to the overall tank.

As someone who's kept so-called "community tanks" forever, I can certainly appreciate the challenge and the allure of keeping multiple fish species together in one aquarium. And I know most of you can, too.

It's interesting to me that in the last decade or so, the hobby concept of a "community aquarium" has sort of evolved from, "A collection of different kinds of cool fishes I like from all over the world, living in one tank"- you know, a "buffet" of fishy favorites, to more of a "curated" collection of fishes that might be found in the same general habitat and location...or even in the exact location...or more specific than that!

I think the shift really started with the rise in popularity of African Rift Lake cichlids. I mean, sure you could keep fishes from different lakes together, but when we collectively learned that each lake not only harbors different fish species, but offers unique environmental parameters and niches that the resident fishes have evolved to live in (like Lake Tanganyikan shell-dwellers, for example), it became more obvious that some degree of specialization was required.

And then we began in earnest to keep other species, like Rainbowfishes and killifishes, which had distinct genetic "races" or populations from various locales that would hybridize if mixed, throwing the already muddled taxonomy and genetics of these fishes into an even greater morass of confusion was definitely something to avoid.

 And then there were the Apistogramma...Yeah, the South American "version" of  African killies...Just plain trouble, from a speciation standpoint, if you mix males and female of different varieties in the same tank. Again, a situation that requires a certain degree of discipline.

Sure, there are like a thousand more examples we could beat the shit out of to make our case, but I think you're getting the idea: Our idea of a "community tank" has sort of evolved with our knowledge of fishes- and I think that's a good thing.

Nowadays, althogh you have "South American"-themed community tanks, "Asian"-themed community tanks, etc., they're more nuanced...Typically centered around regional fishes found in a specific habitat or environmental niche...It's not just, "Hey, that fish is from Thailand...So is TAHT one! And THAT ONE, too!"

A shift.

What's most profound about this shift, in my humble opinion, is that it's enabled us to study more closely- and replicate more closely- the unique environments from which our fave fishes hail. And that leads to a greater understanding of both the fishes and their habitats.

And this is where my interest comes in...

It's entirely realistic, comfortable, and simply "normal" for many of the fishes we play with in aquariums to be kept in close quarters with other species. In one field study of forest streams in the Rio Negro in Brazil (you knew I'd had back there, right?), it was noted that there were up to 20 different species present, all living in close proximity to each other, within distinct niches within the habitat. The population density was an astounding 100 individuals per cubic meter!

That's a lot of fishes! And, with a bunch of niches for them to inhabit- a lot of possibilities...

And the takeaway here isn't that you should pack the hell out of your community tank because some stream in the jungle has a lot of fishes living in a small area of space.


The real takeaway is the fact that the study indicated a significant number of species in that relatively small space, living in different niches within the habitat!

This is where things get interesting, in my opinion, because even in my beloved blackwater streams, you have multiple niches in which fishes live their entire lives, obtain nutrition, protection, and find spawning locations.

The implications for our botanical-style aquariums are manifold...

In our own aquariums, we've seen fishes like Plecos and other catfishes inhabiting and interacting with all sorts of botanical materials, much like they do in the wild. Taking advantage of physical spaces within the greater habitat.

We've seen fishes like Badis, loaches, even wild Betta species living under a canopy of leaves and other botanicals. A variety of fishes living in all sorts of little niches within the botanical scape, exploiting the cover and foraging opportunities that they offer.

This is very cool. This is profound.

In our aquariums set up in a more natural style (in both form and function) the fishes are "sorting things out for themselves" and inhabiting the little niches that they would in the wild. We have great information about these environments, photos of the physical structures found within them, and detailed studies on populations inhabiting these niches.

With terrific access to incredible natural materials and a greater understanding the overall chemical and structural makeup of these habitats, we are able to replicate them as never before!

We're creating aquariums that deliberately foster the development of smaller environmental niches within the greater aquarium structure.

I've spoken with hobbyists attempting to create deep leaf litter beds for specialized catfishes and so-called "Darter Characins", tanks with varied, rich substrate composition to accommodate loaches, tangles of roots for Tetras, etc.  

Perhaps most exciting, we're developing more modern interpretations of the "community aquarium", intentionally layering, populating, and optimizing several "microhabitats" within the same tank. 

What new understanding will we gain by creating these deliberate configurations within our aquariums? What newfound successes will we have with previously temperamental fishes? What reproductive secrets will we unlock- all by providing more faithful representations of the communities and micro niches from which they come?

The mind boggles!

In today's hobby, it's no longer "good enough" for many specialty fish enthusiasts to simply toss in a PVC pipe section for a "cave", or a "Texas Holy Rock" as a hiding or spawning locale for that Pleco or cichlid. For the first time, we are seeing hobbyists really utilize botanical materials from specific geographical regions.

Not simply to satisfy a judge in some snobby aquascaping contest, but to determine if there are advantages for our fishes that may be gained by using the actual materials that are found in a specific region!

For many, the idea of replicating more realistically the environmental niches that these fishes inhabit in the wild is more compelling, fascinating, and proving to be more successful than ever before.

We're at a very special time in the aquatic hobby.

A time when information, technology, technique, communication, and creativity are all intersecting, equipping us with all of the tools- both metaphorically and physically-that we need to create aquariums that may surpass anything we've done in the past, in both form and function.

By studying and sharing information and experiences about the unique niche habitats that many of our fishes come from, we're accelerating the pace of these breakthroughs and discoveries, and maybe- just maybe- further reducing our reliance on wild-collection of some species from their fragile ecosystems, preserving them for future generations to enjoy.

Yeah, there are still great "community tanks" to be made! And there are nuances, niches, and ideas to test and explore...These will drive many of the next innovations in the hobby.

Stay innovative. Stay creative. Stay resourceful. Stay thoughtful. Stay observant...

And Stay Wet.


Scott Fellman

Tannin Aquatics.

April 21, 2019


Never green with envy...

Total confession: I am definitely not an aquatic plant guy. In fact, I'm not even able to identify half the plants out there that are popular at any given time, let alone the "classics" all that well...And the fancy "varietals?"

Yeah, forget about it!

That being said, I've kept plants all throughout my decades of life as an aquarium hobbyist. However, for me, the aquatic plant obsession bug just new bit. I don't know why. I love them. I think planted tank are amazing, and I respect and admire those who are good with them.

Yet, I look at planted tanks and I just don't feel this compulsion inside that screams, "I have to have one!"


Rather, I planted my flag in the "hardscape" department-specifically with botanicals and blackwater and such, and never really looked back. Now, I do currently have a blackwater aquarium with plants at home...And this is strange- it's probably my least interesting or compelling aquarium I maintain right now. Which is odd, because it's a great tank with lots of cool Southeast Asian fishes and tons of potential.

Yet, when I stare into this tank, I'm more likely to say "Meh!" than, "Wow!" 

Now, my planted tank friends tell me that it's largely because I decided to go with notoriously slow-growing plants like Cryptocoryne...Plants that, without the addition of CO2 just sort of "exist", growing incredibly slowly. I mean, they look healthy and colorful, but they are just sort of...there. Of course, going with a large percentage of tissue-cultured plants (the freshwater equivalent of coral frags, IMHO) that were tiny to begin with didn't help, right?


So, this is as good a time as any to discuss the whole idea of plants in blackwater aquariums once again. (Yeah, we've had this discussion a few times!)

The interesting common denominator about this topic- like so many others when it comes to blackwater aquairums, is that there has simply been a lack of good information on the topic- and an abundance of speculation, assumption, and downright misinformation floating about out there in cyberland...

I think the misconception that plants can't grow in blackwater partially originates from the common "inflection point" of, "Blackwater aquariums are unstable/hard to manage/dark and foreboding", and merges with the well-trodden and partially factual "narrative" that says that, since many parts of say, the Rio Negro essentially have no plants, that plants can't live in any blackwater habitats.

I was able to glean some information that might be of use to you in this regard, and with all of the interest, it seems like an appropriate time to be discussing this stuff!

First, let's just clarify the "plants in Amazonia" thingy real fast.

There are two primary areas of interest in our particular "botanical-centric" habitat focus, besides just the better-known blackwater rivers, such as the Rio Negro, where plants are found.

The Varzea are seasonally-flooded forest areas, which are inundated by pH-neutral "whitewater" (ie; not significantly stained by tannins), and can reach significant depths, whereas the Igapo are generally shallow, blackwater environments with relatively low nutrient content and acidic soils. Varzea forests are extremely rich, which leads to a very rich aquatic ecosystem when inundated, and tend to have greater density of aquatic plants. Várzea forest soils have high nutrient contents because they receive high loads of sediment (from the Andean and pre-Andean regions) from the whitewater rivers nearby.

Igapó forests, by contrast, do not receive this seasonal influx of sediments , which is why they have relatively inorganic nutrient- poor soils. Igapo waters are acidic, with a pH ranging between 4 and 5, and are rich in organic materials- particularly humic and fulvic acids. It is also thought by scientists that the seasonal inundation of the Igapo soils creates anoxic conditions, limiting plant growth in general.

So, you CAN keep aquatic plants in blackwater aquaria intended to replicate, to some extent, either of these botanically-influenced habitats. Obviously, the Varzea-type flooded forests are more conducive to aquatic plant growth.

And here is the part which probably feeds into the general  "you can't grow plants in blackwater" myth: 

The other important factor affecting plant growth in these aquatic habitats is light; or specifically, light penetration. This affects diversity of both the terrestrial grasses and aquatic plants present in the waters. In the blackwater Igapo areas, light only penetrates down to depths of  1-2 meters, and many submerged grasses and terrestrial forest plants simply die back from lack of light. And the forest canopy adds to the shading in some areas, further reducing the amounts of light available to plants. Varzea tend to be more "open", and a greater abundance of light, and therefore, light penetration, occurs.

Of course, you can grow Amazonian plants in blackwater aquariums, such as the broad-leaved dwarf Amazon sword plant (Echinodorus quadricostatus), which prefers the dim conditions of blackwater rivers. And notice, I didn't even touch on Asian blackwater plants, like Bucephalandra, Cryptocoryne, etc.

If ever there were "poster children" for blackwater-native/tolerant aquatic plants, either of these two genera would be the ones.

Interesting to me is the use by many hobbyists of low pH substrates and leaf litter in their culture ( a lot of the blackwater Crypt. "players" use Catappa, etc. in a ground up form, almost like a "mulch" of sorts...A cool use for our "Mixed Leaf Media" and "MLM2", I'd say! ). Interestingly enough, many of the so-called "blackwater Crypts" also tend to "melt" if they are in soils that are too nutrient rich...A lot to take in here, but a lot which plays right into our fascination with botanical-style blackwater aquariums!

And what about Africa? It's more than just Anubias...

I think that a considerable amount of time needs to be spent by members of our community simply reaching out to our friends who are into aquatic plants...the knowledge and commonalities are remarkable. We simply need to discuss and understand the realities of keeping plants in blackwater versus the more "traditional" " clearwater" aquarium.


It's a known fact that light doesn't penetrate as effectively in the tinted water of blackwater environments. That's ONE of the reasons you don't see a lot of algae in many blackwater systems. And floating plants, of course, tend to do well-because you don't really have the "light penetration factor" influencing them as much as say, rooted plants. Light penetration is a limiting factor, other things being "more-or-less" equal, right? 

Well, yeah...you can compensate with brighter light...the beauty of LEDs, right? And of course, just having light in our tanks isn't enough.

The other big issue to tackle when keeping aquatic plants in blackwater aquariums is to some extent, the well-trodden opinion that blackwater may be described as more "nutrient poor", and having much lower ionic concentrations of calcium, magnesium, sodium, and potassium than clearwater environments.

So how do you overcome this?

You fertilize your tank- just like you do in a "clearwater" system. You'll probably have to adjust your doses to compensate for the near lack of the above-referenced major ions, but it's pretty much that simple, in my experience. You'll use more fertilizers. And if you're growing plants that rely on rich substrates, like Cryptocoryne, I've found that you really don't have to do all that much differently than you do in a "clearwater" tank.

So, just because the water is dark, doesn't mean you can't keep plants. And hey, if you're a guy like me, who's obsession is with brown instead of green, it simply means that there are lots of different directions you can go in our world.

Stay curious. Stay motivated. Stay diligent. Stay undaunted...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

April 20, 2019


The tangle of Spider Wood...


When it comes to creating hardscape in our aquariums, we tend to fall in love with a few varieties of wood. I mean, sure, we are always looking for different varieties, yet we seem to settle on certain types with incredible predictability. And there is absolutely nothing wrong with that! 

One of the most consistently popular wood types in our hobby is what is known as "Spider Wood."  It has a most unusual root-like configuration, which lends itself well to all sorts of aquascaping applications.

Now, I've always liked this stuff, and we've pretty much always sold this stuff as  "Hand-Selected Pieces" (ie; random ones we pic FOR you!), which are just as good as when we used to sell them as WYSIWYG...And better for you, because it costs less when we don't have to photograph each piece!  I mean, they ALL pretty much have unique attributes and almost every piece looks good from one or more angles.

You can't really go wrong.

And it "plays well with other materials- like Senggani Root, as we've demonstrated in our most recent tank.

You almost can't go wrong, really. Even with a guy like me selecting for you!

Now, I'll be the first to tell you that "Spider Wood", although stupidly easy to work with, has its own set of quirks. It has some really gnarled shapes- which is awesome, but you need to think about it if you're trying to use a few larger pieces in your 'scape. Often the pieces are rather challenging to "fit together" if your goal is to make it look like they are part of one "organic formation", if you will, so you really have to use some forward vision if that's your goal and you're using the larger-sized pieces.

The "nano-sized" ones are ideal for this type of project.

I mean, if you look closely at a lot of displays that use this wood, they look sort of like a bunch of little peices all stuck together. Which, I suppose, is part of the "charm" of the stuff. You have to envision it after a month, covered with a "patina" of biocover, surrounded by decomposing botanical botanicals...


My understanding that what the aquatic trade refers to as "Spider Wood" is the roots of Rhododendron (aka Azalea), a genus of over a thousand woody plants found in Asia and North America. Like everything else in the aquarium hardscape trade, the exact species or origins are kept shrouded in a sort of deliberate mystery. That being said, it's no mystery why the stuff is popular! It looks pretty cool...once you figure out how to use it! 

And, as an added "bonus", this stuff releases a lot of nice, water-tintitng tannins...something that freaks the f--- out of most hardcore aquascapers (much to my sadistic delight, as you know), but something that our tribe just loves! Oh, and the plant (and I think likely by extension, the roots) is known to offer "..possible anti-inflammatory and hepatoprotective activities" which may be due to the antioxidant effects of flavonoids or other phenolic compounds and saponins the plant contains...

If you recall, some of these same substances are known to occur in Catappa leaves, and there are documented fish health benefits of catappa, validated in scientific research.


Oh, and it does tend to recruit a fair amount of gooey fungal/biofilm growth shortly after submersion, often to the horror of the unaware...So, if ever there were a candidate for "pre-soaking" wood before using in the aquarium, "Spider Wood" is it. Granted, this growth will usually subside after a few weeks of submersion, and some well-timed scrubbing with a soft-bristled brush.

Holy detour, Batman! Okay, so back to the scaping thing...

It's relatively lightweight. REALLY gnarled in appearance...and pretty much perfect for many types of aquascaping ideas! 

And that's about alI I have to say about THAT!

Stay creative. Stay inspired. Stay diligent. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

April 19, 2019


Out of the "frying pan..."


Yes, it's time for me to start ruminating about stuff that I've been plying with in my head for years...You know, the idea of an aquascaping contest. Now, with my complete disdain for the typical aquascaping contests- the absurd rules, the endless arguments over format, attitudes, etc, I feel like I'm likely opening up myself for more trouble... 😂

I know we talked about the "Igapo Challenge" some time back...It's something that I know we'll do later...However, I think our first contest needs to have a broader appeal...

It needs to be a bit more inclusive, and do more than just reward the best-looking tank.

That being said, I think a contest can perform some valuable functions in our world. First, it can help show the current state of the art in truly natural aquariums. Not just blackwater aquariums...As we've seen, the world we've all evolved here at Tannin has grown to encompass botanical-style blackwater, brackish, planted, and other types of unique systems.

I'm trying to figure out criteria...I mean, I will personally have to restrain myself from railing on any of our judges who look at "Golden Ratio", "Iwagumi" rock placement, or other conventional constructs like that. Also, I wouldn't want to hold entrants to being compelled to enter stuff as specific as "Small meander adjacent to Rio Parauari, high water mark, 30km north of the town of Alto Maues..."  Not only would that degree of pretentiousness make me want to vomit- I think it would defeat the purpose of this contest idea. I don't want to encourage insanity. This would not be a strict "biotope" contest. It's that whole "biotope-inspired" thing.

That's why, I'd vet the judges carefully. It would just be ugly, otherwise!  I mean, sure, I'm not saying that we'd want to see entries like,  "Liquid Methane River on the Saturnian moon of Titan"- that's too geeky and weird even for me.

Oh, and if you give your entry a name; you know, "The wandering trail to Enlightenment" or something like that- immediate disqualification. Seriously. 😍 

Just enter something cool. Describe what it purports to represent.

We'd likely have some set of questions that comes with entry- so that observers and judges alike can learn from your work...

The idea- our "mission statement", if you will- would be to create a contest- an exhibition, really- which celebrates our love of the "natural style" aquarium. And more important, celebrates the uniqueness; the aesthetics of Nature- and the function of the aquarium. Entrants won't be rewarded for fantasy-style "diorama-style" tanks, for sure! 

I suppose, the whole thing also requires us to have a definition of what we think a "natural style aquarium" is in our little contest. Well, here are some of my initial thoughts:

First off, the aquarium should incorporate a large percentage of materials such as botanicals, leaves, driftwood, etc., utilized in such a manner as to create a functional representation of a wild aquatic habitat. In other words, an aquarium that operates, not just looks good.

I think that vivariums, paludariums, and aquariums should all be entered into the mix...No separate categories for them. Because we will likely evaluate a given system  on both aesthetics and function, and we want to encourage "cross-over" work by aquatic hobbyists- I don't see any reason why we should have all sorts of complicated category distinctions.  Same with display size. I see no reason why a 5-gallon aquarium can't be evaluated using the same criteria as you would a 250-gallon aquarium.


Oh, and I think it would be important to show some "evolution" of each entry. In other words, more than just a "here's the rock work as we set up the tank" bullshit. I'm talking, several shots taken throughout the "pre-entry" life of the tank, from startup to submission- perhaps taken over the course of 4-5 months. Yeah- any talented 'scaper can do an "instascape"- a talented aquarist can evolve and manage it over time.

This would, of course, necessitate a longer time window for entries. Like, there would be an entry period, and then an "evolution period", and finally, the closing date when submissions need to be received by.

And stuff like decomposition, detritus, biofilm- even algal growth would not be penalized. In fact, unless it's specific to a given niche you're attempting to replicate, I'd think that we'd actually look suspiciously on any tank that looks super pristine and perfect! Of course, I'm not saying to enter a poorly-maintained fish-death factory...What I am suggesting is that we  should see entrants which attempt to "meet Nature where it is"- that being the intersection of science, art, and evolution.

Nature is not a perfectly ordered, pristine place. Your entries don't need to be, either. 

And then there would be a strong judging component for originality and innovation. Like, if you tackled some problem uniquely to create your functionally aesthetic entry, we'd love to hear about it. No secrets in this game. It's as much about sharing technique as it is about exhibiting the results of it. And no, you don't have to only use materials you've purchased from Tannin in your entries. Sure, we'd love to see some stuff, but to make that a requirement would be- well, just sort of lame.

And of course...prizes. If we're asking you to do a 6-month commitment to a contest, they have to be good. So, likely, we'll have stuff like aquariums, lights, accessories, gift cards, etc.

Likely, there would be a nominal entry fee (like $10USD or less), which would cover some of the expenses for administering and promoting the contest and entries. We'd really want to share your work with the world.

And I think we'd have a first-third award schedule. And perhaps a couple of other categories? Like, "Most Unique" or "Most Innovative"- something like that?

Well, that's what I have for you so far...I'm absolutely open to hearing what you think- to your suggestions, concerns, etc.

My God, what have I unleashed now?

"Out of the frying pan- into the  damn fire, right?"


Until next time...

Stay creative. Stay thoughtful. Stay diligent. Stay unique. Stay generous...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




April 18, 2019


The art of habitat representation: A case study...

As an observer of modern aquascaping- in a variety of forms, I've spent quite a bit of time looking at flooded forest floors. This interesting habitat offers incredibly interesting aesthetics and function. It's a habitat which gives us the opportunity to not only be creative, but to learn about its unique dynamics and function.

If we look at this habitat a little deeper, we can perhaps pull out some components of it, and consider what materials we could use to replicate its unique features. This is something that I love...assessing which materials would do the job. We have received so many requests about "...which ones do I use?" that it made a lot of sense for us to address this in terms of what we offer. Now, I realize that part of the fun is assessing and scheming and curating for yourself; however, we can't help but push a few ideas into your head to perhaps speed along your process!

Now, we've talked about flooded forest floors many times, but not in this specific context.

What would be some "cornerstone" materials that you'd use to represent this habitat? Well, let's break it down:

First, a forest floor has soil. It's sort of a "dirty" place (pun kind of intended...).

In our case, we could use a combination of standard aquarium substrates, like sand, perhaps combined with terrestrial soils, or planted aquarium soils. In one of my recent aquariums, I utilized a fine aquarium sand, coupled with some ground-up, clay-based  aquatic plant soil (Ultum Nature Systems "Control Soil). I selected this material because the aesthetic and grain size, when combined, creates something that looks very much like the soils you'd find on a tropical forest floor.

And of course, no flooded forest floor would be complete without roots, branches, and stems. My recommendations from our "portfolio" would be one of more of the following: Oak Twigs, Senggani Root, or even "Spider Wood." Each brings its own aesthetic and function to the aquarium representation of this habitat.

You could keep the "roots and twigs" to a minimum, placed in a "flat" configuration on the substrate, or let some of them creep up into the "vertical", consuming a bit of the negative space in the aquarium. If you're using materials like the Senggani Root", there is the option of orienting them in a variety of ways. You could even cut up and utilize "bits and pieces" of these materials in lots of different ways, in order to represent that element of the habitat.

The other, and perhaps, most obvious component of this habitat is leaves. Whenever you have trees overhead, you're pretty much guaranteed to have lea yes failing to, and accumulating on the forest floor. And of course, when the waters arrive, the leaves become a dominant part of the newly aquatic habitat.

As you know, we're really into leaves, and we have a pretty good variety of different leaves available. It's really about what you like, the aesthetic you're looking to achieve, and the "scale" of the aquarium.

And of course, seed pods are perfect to use in this type of representation. Some of my personal faves would be smaller items, like Mokha Pods, Calotropis Pods, Dregea Pods, and Jacaranda Pods.  Obviously, the choices are endless. I like these particular materials because they have varying degrees of durability, offer a diversity of shapes, and are of a "scale" that can work even in a smaller aquarium.

And of course, there are other possibilities to replicate this habitat. You can utilize larger materials which represent tree trunks and other large, buttressing structures which end up on the first floor. Larger pieces of driftwood, such as our "Malaysian Driftwood" and "Asian Driftwood," can represent these materials in a most effective way. If you can source  very thick, substantial pieces to represent a tree trunk, either in the "upright" or "fallen" condition.

And then, there are those other materials- such as bark pieces; specifically, Red Mangrove Bark, which comes in larger, more "workable" sizes. Bark not only adds compounds like humic substances and tannins to the water, it creates a rather durable substrate upon which various microorganisms and fungi can anchor and proliferate- adding to the "functional" aspects of the aquarium habitat.

One additional component that you will find on a flooded forest floor would be terrestrial grasses. Many of the grasses in these forests are durable enough to survive these periods of inundation.

Now, we may not have access to the exact species of grasses that are found in these habitats (although you can do some research in academic papers online and find them); however, we can find some species which are representative of them. We could even utilize riparian plants- or perhaps even some aquatic plants (gulp), like Sagittaria, which can really work. Again, it's about representing- as opposed to strictly replicating- components of this habitat.

At the end of the day, about the best we can do is present to you some aspects of the habitat, and recommend some of the materials that you can use to recreate it- or aspects of it- in your home aquarium. And of course, there are numerous other materials you can use from our selections, or materials that you can collect yourself. The art and science of natural aquarium keeping is an evolving and enjoyable one!

And with that...

Stay interested. Stay creative. Stay observant. Stay diligent...

And Stay Wet.


Scott Fellman

Tannin Aquatics