Fostering a relationship...

"In order to be irreplaceable, one must always be different..." - Coco Chanel

I believe that it's vitally important to take a different approach to seemingly mundane topics in the aquarium hobby from time to time. It makes us think. It challenges our skills, our mindset, and what we take for granted.

We have talked ad nauseam about the relationship between terrestrial and aquatic habitats. It's so fundamental that we almost don't consider it in the hobby. A real shame, because within this relationship, there may be found many valuable takeaways which can unlock some secrets to fish care.

We have studied and extensively embraced the interactions between materials like branches and roots and the aquatic environment. Yet, there are many others which we should explore more intensively, IMHO.


The relationship between water and soil is actually a remarkably complex one, with biological implications that we probably haven't thought about very much as hobbyists. Studying how water gets to the aquatic habitats- or how it creates them- is a critical key to understanding the needs, behaviors, and adaptations of our fishes!

During that journey into the (aquatic) habitats, materials like humic substances, minerals, etc. will be absorbed into the water from the surrounding soil. Yeah...that's the interesting part: The surrounding geography and geology have as much to do with the ultimate water characteristics of a given habitat as anything else!

Like so many things in Nature, everything is somehow interrelated! Even fishes play a role in shaping the environment to a certain extent.

Fishes which consume matter found in the substrate (detritivores) and other materials in the substrate (omnivores) also play a fundamental role in the transportation of organic carbon, which is a source of energy for downstream fish communities.

Through their foraging activities, these fishes enhance the "downstream transport" and processing of organic material and ensure the proper functioning of the aquatic system and its biological community.

So, we have the terrestrial environment influencing the aquatic environment, and fishes that live in the aquatic environment influencing the terrestrial environment!

These interdependencies are really complicated- and really interesting!

The overriding them, again, is that geology influences water composition. 

Once again, bringing it all back to a more practical aquarium point of view, I can't help but wonder if working with different types of substrate materials (soils, sands, etc.) in our "makeup water" containers could yield some similar effects to those we see when we steep leaves and botanicals in the water.

It's an easy idea to experiment with, isn't it?

Could the right combination of soils in both our makeup water containers and even in the aquarium create even more realistic water conditions for our fishes and aquatic plants?

One can only wonder...

Would it make sense to steep some aquatic substrate in the containers in which we prepare makeup water for our tanks, much as we have done with leaves and peat moss and such for years?

I think it makes a ton of sense.

What could you expect from utilizing soils or specialized substrates in your water preparation process? 

Well, for one thing, many substrates will likely have some impact on the pH or alkalinity of the water, both in the prep container and ultimately, in the aquarium. So, wouldn't it make sense to experiment with substrates and soils as a water preparation "vehicle?" You could prepare water for use by creating the same water conditions as you'd find in your aquarium.

I think it would be a cool experiment that could ultimately simply evolve into a "process" for conditioning water for our aquariums. 

We're seeing more and more specialized "aquatic soils" for plants which are designed to simulate some aspects of the natural habitats in which they are found. Well, fishes are typically found in those habitats, too, right?


Why should the plants have all the fun?

They shouldn't.

Wouldn't it make sense to create some specialty substrates for use in tanks which feature fishes and not just plants (or are even devoid of plants?). What potential benefits for our fishes could be gained by using these more "technical"  substrates in our fish-centric botanical-style blackwater aquariums? 

Substrates, as we've discussed, have profound impact on the ecology of natural aquatic habitats, as well as aquariums.

That was the whole basis behind our "NatureBase" line of substrates. It's been a while since we've launched our first ones ("Igapo" and "Varzea"), with several more formulations nearing release ("Borneo", "Mangal", and "Floresta")- and the positive feedback from you, our customers, has been nothing short of incredible!  We think that our focus on well-researched, small-batch-formulated substrates just might change the way we think about substrates in the hobby. 

At the very least, the idea will impact how we integrate substrates into aquatic displays. As a hobbyist, I'm now busy designing aquatic displays around the substrate, and its form and function...A very different approach than I've taken in the past! 


It's been a ton of fun, too!

It all began by looking at the big picture, and by thinking and talking about the stuff we haven't given much thought to in years past. 

Substrates are not just "stuff you put on the bottom of the aquarium" to us. Much like in Nature, they are diverse harbors of life, ranging from fungal and biofilm mats, to algae, to epiphytic plants. Decomposing leaves, seed pods, and tree branches further enrich the substrate, creating a complex web of life which helps the fishes we're so fascinated by, to flourish.  

It's very different than what we've perceived to be "natural" in the aquairum for generations. And, if you look at the substrates in natural aquatic habitats objectively and carefully, they are beautiful.

I'm fascinated by the different types of soils or substrate materials which occur in blackwater systems and their clearwater counterparts, and how they influence the aquatic environment.


We can study and attempt to replicate some of these processes and relationships in the aquarium, and we should give due attention to researching the terrestrial habitats which surround the aquatic ones...or habitats, such as igapo, which transition between terrestrial and aquatic.

Taking the time to study these habitats in their "terrestrial" state and understanding the composition of the soil and plant species which reside in them can make a huge contribution to our knowledge as we attempt to replicate them in our aquariums.

Yeah, if you would have told me twenty years ago that I'd be reading scientific papers about, well- dirt- on the forest floors of Amazonia, I would have been like,

"Um, yeah...right..."

However, the reality is that in order to replicate habitats like flooded forests as an aquatic habitat, we need to understand them in their terrestrial state as well. Our friends who keep frogs and other herbs have an interesting understanding of these habitats, and we would do ourselves some good reaching out and discussing this sort of stuff with them!


Again, give some real thought to the idea of topography, geology, and substrate impacting the aquatic environment. It's hardly an alien concept to aquatic plant enthusiasts. They've been using specialized substrates and additives for years to grow healthy aquatic plants.

With water finding its way into the streams, rivers and other areas from so many sources, there is probably so much we can learn from finding out more about the surrounding areas themselves, and how water ultimately makes it into the bodies of water we are so obsessed with. This is an area of study in the hobby that's really wide open for advancement, IMHO.

The possibilities are endless here!

In habitats such as  blackwater streams, the color is a visual indicator of an influx of dissolved materials that contribute to the "richness" of the environment. Indeed, a blackwater environment is typically described as an aquatic system in which vegetation decays, creating  tannins that leach into the water, making a transparent, acidic water that is darkly stained, resembling tea.

Of course, there's more to it than that.

Despite the appearance, as a general rule, blackwater rivers are lower in nutrients than clear rivers. Why? They have very low concentrations of major ions, such as sodium, magnesium, potassium, and calcium, and lower conductivity and typically low levels of dissolved solids.

Blackwaters originate from sandy soils. High concentrations of humic acids in the water are thought to occur in drainages with what scientists classify as "podzol"- sandy soils. "Podzol" is a soil classification which describes  an infertile acidic soil having an "ashlike" subsurface layer from which minerals have been leached.

That last part is interesting, and helps explain in part the absence of minerals in blackwater.

Think about what that means for just a second, and about the many factors and processes that influence the water characteristics of these unique habitats.

Geology is the key.

Wouldn't it be interesting, when contemplating more natural biotope/biotype aquariums, to study and take into consideration the surrounding geology and physical characteristics of the habitat?  

As we know now, the influence of factors like soil and the surrounding geology- rocks, specifically- play a huge role in the chemical composition and appearance-of the water. It's really no different in the aquarium, right?  Except we've been playing with the "software" side- the use of terrestrial materials like seed pods, leaves, and branches.

Tannins from wood and botanical materials will leach into the water, providing the characteristic "tint" that we've become so accustomed to in our little niche. Well, so will soils and other substrate materials, right?

So, we should place as much emphasis on soils and geology.

Studying the characteristics of the igapo and varzea forests of Amazonia, for example, has yielded som interesting insights. However, it is just a start...these are the "textbook" examples of geologic influence on the aquatic environment- something that we can really run with in our aquarium interpretations of this habitat.


And the idea of incorporating botanical materials into specialized substrates is practically a replication of what occurs in Nature. We see it everywhere, and the impacts are profound.

Yes, I also have this irresistible curiosity about the potential of botanical-influenced substrates to foster denitrification. With the diverse assemblage of microorganisms and a continuous food source of decomposing botanicals "in house", I can't help but think that such "living substrates" create a surprisingly diverse and utilitarian biological support system for our aquariums.

I think that the idea of an "enriched substrate" will become an integral part of the overall ecosystems that we create. Considering the substrate as both an aesthetic AND functional component- even in "non-planted" aquariums, opens up a whole new area of aquarium "exploration."

The potential opportunities and breakthroughs are there...We just have to dig in-literally- and go after them! Studying the interdependencies and relationships between water and land is just the start!

Stay fascinated. Stay curious. Stay excited. Stay resourceful. Stay creative...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




Scott Fellman
Scott Fellman


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