What do we do?

It's been over 5 years since we've started Tannin Aquatics, and the global movement with botanical-style aquariums is really starting to take off! I've been very proud to have played a small role in the growth of this movement!

People often ask me about the kinds of aquariums that we create and play with. They ask a lot about blackwater aquariums- which are incredibly cool. However, the term "blackwater aquarium" to me seems so limiting and somewhat restrictive when used to describe what we do.

And perhaps even misleading, really.

I tell people that I play with "natural, botanical-style aquariums."

So, here's the thing: When we talk about "botanical-style aquariums", we're not just talking about blackwater aquariums, or even aquariums with deeply tinted water. Now, sure, I love them- a lot of us do; however, what we proffer is not just a way to "make your water dark." Rather, it's about the idea of utilizing botanical materials to impact the physical, chemical, and ecological aspects of our closed aquarium ecosystems.

To state that the botanical-style aquarium movement is just about blackwater is to sell it short. There are so many hobbyists who enjoy the look and benefits of using leaves and other botanical materials in their tanks without the tinted water. They simply admire the look and the benefits these types of aquariums offer. So, it's important for us to mention this now and again, so that we don't get confused or feel that there is some "underlying rule" or something about how to do this stuff "correctly."

Now, think about this.

You can have a perfectly crystal-clear aquarium with blue/white water and tons of leaves and botanicals. For some reason, the popular perception in the "mainstream" aquarium world is that you can only have a botanical-style aquarium if you have tinted water.

Not true. A little carbon and a lot of pre-soaking of your leaves and botanicals, and a "crystal clear botanical-style aquarium" is yours.

The other misconception which has hung around forever is that, "ANY time you have tinted water, it's soft and acidic..." It seems to be that we have this mental equivocation that "brown water=soft, acidic water"- and the reality is that this is simply not true. It's part of the reason why we receive lots of emails from hobbyists wondering why their highly alkaline, extremely hard water is still just that- even after adding a bunch of leaves and seed pods to their tank.

In my opinion, we as a hobby often have expectations field by a fundamental lack of understanding about the habitats we seek to represent. We rely on stuff like,  "I heard that..." or "This guy on YouTube said...", rather than taking the time to do some homework for ourselves.

A shame, really. 

And as a result, we fall back on generalizations and characterizations that aren't entirely consistent with the facts- which leads to confusion, the propagation of misinformation, and even disappointment among hobbyists.

It is absolutely possible to have a deeply tinted aquarium with 8.4pH and a GH of like 10 or more. The color simply indicates the presence of tannins and humic substances in the water, both of which will have surprisingly little impact on the characteristics of hard, alkaline water. 

I've seen this "look" in Nature many times. In fact, in many hard, alkaline bodies of water, the water is still stained brownish because of the presence of soils and leaves and other plant materials.

Is it "blackwater?" 

Well, not in the strict ecological definition.

Ecologists will tell you that blackwater has a different ionic composition than "whitewater"- as it is very low in sodium, magnesium, calcium, and potassium and has an acidic pH because of the lack of buffering capacity, low dissolved solids, and the high concentration of tannins and fulvic acids present in the water.

That's science, and you can nuance it all you want, but facts are facts. When I see these arguments on hobbyist forums about what the definition a "blackwater aquarium" is, and I'm tapped to give my two cents, I typically will chime in with something like, "It's an aquarium in which the water characteristics are (insert descriptor above!)"

Color isn't everything. 

The color is only a partial indicator of "blackwater" in the literal sense. Not all dark water rivers and streams are "blackwater" in that technical sense. 

I have kept several successful "tinted" brackish water systems that loo for all the world like what you'd expect to see I the Orinoco or somewhere like that, except that they were hard, alkaline, and had a specific gravity of 1.010! Would you call it a "blackwater" system?

You could, but you'd be wrong.


Nature offers lots of other examples.

I haven't really done a ton of research into the habitats of wild livebearers, but I've seen a few pics of their natural habitats from underwater, and the water was anything but crystal clear and blue/white! Rather, it was turbid, slightly brownish, and decidedly hard and alkaline!

This is something that we as hobbyists have to get our heads around, too. Color of the the water is simply not indicative of the pH/hardness, and many other characteristics of the environment in which it is found.

And, as we've discussed many times before, even the clarity of the water often has no bearing on its "quality." 

It's a distinction that neophytes to our world should make note of. The "rap" on blackwater aquariums for some time was that they look "dirty"- and this was largely based on our bias towards what we are familiar with. And, of course, in the wild, there might be some turbidity because of the runoff of soils from the surrounding forests, incompletely decomposed leaves, current, rain, etc. etc.

None of the possible causes of turbidity mentioned above in these natural watercourses represent a threat to the "quality", per se. Rather, they are the visual sign of an influx of dissolved materials that contribute to the "richness" of the environment. It's what's "normal" for this habitat. It's the arena in which we play in our blackwater, botanical-style aquariums, as well.

My obsession with brackish water habitats has, over the years, gotten me far, far away from the hobby-supported mindset that these environments are supposed to be crystal clear and contain white sand and grey rocks. The reality of Nature is completely different. Mangrove habitats are another great example of "you can't tell a book by its cover." The water is not exactly crystal-clear, and often colored.  

Muddy, nutrient- rich, filled with mangrove leaves, and stained a bit from tannins. Beautiful in a very different, yet oddly compelling way.

And of course, turbidity caused by sedimentation and the dissolution of soils into the water creates an entirely different class of natural aquatic system.

With our recent obsession with substrates, we've been able to replicate many of the characteristics of these unique, heavily terrestrial-influenced systems by using materials which replicate the composition of the soils surrounding these aquatic habitats.

Obviously, in the closed environment that is an aquarium, "stuff" dissolving into the water may have significant impact on the overall quality. Even though it may be "normal" in a blackwater or brackish environment to have all of those dissolved leaves and botanicals, this could be problematic in the aquarium if nitrate, phosphate, and other DOC's contribute to a higher bioload, bacteria count, etc.

It's why testing and monitoring, coupled with regular maintenance practices, are of paramount importance in botanical-style aquariums of any kind.

Again, though,  I think we need to contemplate the difference between water "quality" as expressed by the measure of compounds like nitrate and phosphate, and  visual clarity. As you might surmise, it is absolutely possible to have turbid, tinted water and fantastic water quality!

In my home aquariums, and in many of the really great natural-looking blackwater aquariums I see the water is dark, almost turbid or "soupy" as one of my fellow blackwater/botanical-style aquarium geeks refers to it. You might see the faintest hint of "stuff" in the water...perhaps a bit of fines from leaves breaking down, some dislodged biofilms, pieces of leaves, etc. Just like in nature. Chemically, it has undetectable nitrate and phosphate..."clean" by aquarium standards.

Sure, by municipal drinking water standards, color and clarity are important, and can indicate a number of potential issues...But we're not talking about drinking water here, are we?

So, the whole thing of water color and the practice of utilizing botanical materials and substrates to influence the look, characteristics, and ecology of an aquarium is a dynamic, constantly-evolving art. The moniker "natural, botanical-style aquarium" is so much more descriptive of the type of work that we do as a community, rather than just falling back on the "default" to "blackwater aquariums" because the water has a sort of "tint" too it.

To "pigeonhole" the many different approaches we all take into one category like "blackwater" is to overlook the diverse, dynamic, utterly compelling variety of aquatic habitats that the world has to offer. 

Let's concentrate more on the practices than the "quantification" and descriptions. Those will sort themselves out over time as we refine our practices, ideas, and executions. We need not limit what we do to overly-specific categories for the sake of convenience.


Rather, let's celebrate the art and sicken of natural, botanical-style aquariums, and see where our imagination, ideas, and Nature take us!

Stay creative. Stay inspired. Stay curious. Stay studios. Stay unbounded by convention...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


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