Starting at the bottom...

It's pretty funny to see how our world has changed a bit over the years. What was once considered completely crazy is now only seen as a bit.."odd."

Hey- progress, right? Yeah, we'll take it.

Since the inception of our company, we've been encouraging everyone to experiment with utilizing botanical materials for a variety of purposes in our blackwater/botanical-style aquariums. And one of the things we've been playing with has been the practice of mixing various botanical materials into the substrate directly.

Now, this isn't exactly a revolutionary, earth-shattering practice. However, it is something which we believe hasn't been played with outside of the "dirted tank"  concept in planted aquariums. Of course, the whole idea of planted blackwater aquariums is absolutely a "thing"- something that we feel will simply be a type of aquarium that aquatic plant enthusiasts set up in the near future as a matter of practice. We've done a lot of experimenting with this as a group and I think it's more and more common all the time!

However, the idea of creating rich, diverse botanical-influenced substrates for the purpose of infusing tannins, humic substances, and other compounds- as well as creating a "matrix" for the growth and propagation of beneficial micro and microfauna. Yeah, using a botanically-infused substrate to create a unique, ecologically diverse, functional, and aesthetically interesting affect on the aquarium- even one that doesn't have aquatic plants in it- is a sort of different approach.

First off, the question of why you would do this looms large. 

Well, you could start with Nature again...

If you really think about it, the "traditional" aquarium substrates of sand and gravel are essentially biologically "inert" materials, typically devoid of anything except minerals and carbonate ions that are of use to the aquarium. The real "magic" comes when we introduce life forms- or, in our practice- the materials which encourage and support biological function and diversity.

And of course, when you're talking about creating a rich substrate, consisting of decomposing organic materials (leaves, coco-fiber, and other botanicals containing lignin, etc.), that creates a matrix that may eventually consist of- and perhaps accumulate- what we'd collectively call "detritus." 


So the ^**&%$ what? 😆

Is "detritus", or other finely processed organic material the "doomsday machine" that will destroy your aquarium?

I don't think so.

I know-we all know- that uneaten food and fish poop, accumulating in a closed system can be problematic if overall husbandry issues are not attended to. I know that it can decompose, overwhelm the biological filtration capacity of the tank if left unchecked. And that can lead to a smelly, dirty-looking system with diminished water quality. I know that. You know that. In fact, pretty much everyone in the hobby knows that.

Yet, we've sort of heaped detritus into this "catch-all" descriptor which has an overall "bad" connotation to it. Like, anything which is allowed to break down in the tank and accumulate is "bad."

We're not talking about a substrate composed entirely of uneaten food and fish poop here.

The definition as accepted in the aquarium hobby is admittedly kind of sketchy in this regard; not flattering, at the very least:

"detritus is dead particulate organic matter. It typically includes the bodies or fragments of dead organisms, as well as fecal material. Detritus is typically colonized by communities of microorganisms which act to decompose or remineralize the material." (Source: The Aquarium Wiki)

That being said, everyone thinks that it is so bad.

I'm not buying it.

Why is this necessarily a "bad" thing?

In nature, the leaf litter "community" of fishes, insects, fungi, and microorganisms is really important to the overall tropical environment, as it assimilates terrestrial material into the blackwater aquatic system, and acts to reduce the loss of nutrients to the forest which would inevitably occur if all the material which fell into the streams was washed downstream!

The key point: These materials foster the development of life forms which process these materials. Stuff is being used by life forms.

And finely-grained botanical materials not only provide a substrate upon which these organisms can grow and multiply- they provide a sort of "on board nutrient processing center" within the aquarium. In my experience, based on literally a lifetime of playing with all sorts of combinations of materials in my aquariums' substrates ('cause I've always been into that stuff!), I cannot attribute a single environmental lapse, let alone, a "tank crash", as a result of such additions.

A well-managed substrate, in which uneaten food and fish feces are not allowed to accumulate to excess, and in which regular nutrient export processes are embraced, it's not an issue, IMHO. When other good practices of aquarium husbandry (ie; not overcrowding, overfeeding, etc.) are empIoyed, a botanically-"enriched" substrate can enhance- not inhibit- the nutrient processing within your aquarium and maintain water quality for extended periods of time.

Like many of you, I have always been a firm believer in some forms of nutrient export being employed in every single tank I maintain. Typically, it's regular water exchanges. Not "when I think about it', or "periodically", mind you.

Nope, it's weekly. 

Now I'm not saying that you can essentially disobey all the common sense husbandry practices we've come to know and love in the hobby (like not overcrowding/overfeeding, etc.) and just change the water weekly and everything's good. And I'm not suggesting that the only way to succeed with adding botanical materials to the substrate is to employ massive effort at nutrient export; the system  otherwise teetering on a knife's edge, with disaster on one side and success on the other. 

Our aquariums are more resilient than that. If we set them up to be.

There is a lot of science to sift through about natural river/stream/pond substrates and how they function in the wild, and much of this can be applied to what we do in our closed aquariums. Of course, an aquarium is NOT a stream, river, etc. However, the same processes and "rules" imposed by Nature that govern the function of these wild ecosystems apply to our little glass and acrylic boxes. It's a matter of nuance and understanding how they work.

I'd love to keep us in the mindset of thinking about our aquariums as little "microcosms", not just "aquatic dioramas."

And of course, the whole idea of a substrate enriched with botanical materials is completely in line with the practices of a "dirted" planted aquarium. In our case, not only will there be an abundance of trace elements and essential plant nutrients be present in such a substrate, there will be the addition of tannins and humic substances which provide many known benefits for fishes as well. The best of both worlds, I think.

It's about creating an entire ecosystem.

Embracing and fostering not just the look, but the very processes and functions which take place in natural aquatic systems. Is it as simple as crushing some leaves, adding some coconut-based material, covering it up with sand and you have an instant tropical stream? No, of course not. You need to look at things sort of "holistically"- with an eye towards nutrient export and long-term maintenance. 

Like so many things we discuss here, I admit that simply don't have all the answers.

In fact, I admit that I probably have more questions than answers. My experience at enriching substrates with all sorts of materials has been very positive- most recently, with my "tinted" brackish water  mangrove aquarium. This tank features an abundance of different substrate materials, including decomposing mangrove leaf litter and other botanical materials.

It's been so biologically stable from almost day one as to be sort of "boring..." Phosphate and nitrate (the traditional biological "yardsticks" for analyzing aquarium water quality) have remained virtually undetectable on our hobby-grade test kits. This despite what is arguably one of the "dirtiest" (in traditional aquarium parlance, at least!) substrates I've ever created. 

However, we need more experimentation.

What is the takeaway here?

I think the big takeaway is that we should not be afraid to experiment with the idea of mixing various botanical materials into our substrates, particularly if we continue to embrace solid aquarium husbandry practices.

In my opinion, richer, botanically-enhanced substrate provides greater biological diversity and stability for the closed system aquarium. 

Is it for everyone?

Not for those not willing to experiment and be diligent about monitoring and maintaining water quality. Not for those who are superficially interested, or just in it for the unique aesthetics it affords. 

However, for those of you who are adventurous, experimental, diligent, and otherwise engaged with managing and observing your aquariums, I think it offers amazing possibilities. Not only will you gain some fascinating insights and the benefits of "on-board" nutrient export/environmental "enrichment"- you will also get the aesthetics of a more natural-looking substrate as well.

Another week. Another challenge. Another set of questions. And another opportunity for us to provide some of the answers.

Jump in there...

Stay excited. Stay diligent. Stay methodical. Stay open-minded. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


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