Land and water, working together. Embracing the transformation.

As we've discussed so many times here, the idea of mixing of elements- soils, roots, and seed pods is a fundamental aspect of the botanical-style aquarium.

If there's one consistent lesson that we keep returning to, it's that land and water are inexorably linked together. And I think that when we contemplate the dynamic of how water and the terrestrial environment interact, it makes us look at aquatic habitats- and our aquariums-a bit differently.

The forest floors of South America are a prime example of how the terrestrial environment and the aquatic are linked, and ecologically dependent upon each other. What drives this relationship?

Well, it starts with...rain.

Rain does more than just bring life to the land- it influences the existing watercourses, which in turn, influence the terrestrial environments. Torrential rains are a sort of catalyst for the formation of the Igapo. After several weeks of rain, the water levels in the rivers rise significantly. Often several meters, and the once dry forest floor fills with water from the torrential rain and overflowing rivers and streams.

The Igapos are formed. 

Flooded forest floors.

The formerly terrestrial environment is now transformed into an earthy, twisted, incredibly rich aquatic habitat, which fishes have evolved over eons to live in and utilize for food, protection, and spawning areas.

All of the botanical material-shrubs, grasses, fallen leaves, branches, seed pods, soil, and such- is suddenly submerged. Over time, significant water levels create strong currents, which re-distribute the soils, sediments, leaves and seed pods and branches into little pockets and "stands", affecting the (now underwater) "topography" of the landscape.


From an ecological perspective, this transformation from terrestrial to aquatic presents challenges- and opportunities for the organisms which live in these habitats. The ecological adaptations that the inhabitants are required to make are fascinating and dynamic. As the rain continues to fall, branches and stems of trees, once higher up in the forest ecosystem, become an enticing hiding place or foraging area for fishes, which can now easily access them.

Leaves begin to accumulate.

Soils dissolve their chemical constituents- tannins, and humic acids- into the water, enriching it. Fungi and micororganisms begin to feed on and break down the materials. Aquatic insects and diverse organisms as well-known as copepods and as unusual as tree sponges- come to life. 

Land and water working together.

It's an intimate, interrelated, "codependent" sort of arrangement!

I believe that it's important to think of the relationship between the terrestrial habitat and the aquatic one when visualizing the possibilities of replicating nature in your aquarium in this context.

We've talked about the idea of "flooding" an aquarium setup designed to replicate an Amazonian forest for a while now. The so-called "Urban Igapo" idea is fascinating, exciting, and becoming sort of "well-trodden territory" now, with lots of people in our community embracing the idea and doing amazing executions!

It's been incredibly fun for me, sort of attempting to simulate some of the processes which happen seasonally in Nature. With the technology, materials, and information available to us today, the capability of creating a true "year-round" habitat simulation in the confines of an aquarium/vivarium setup has never been more attainable.

Now, that's all well-and-good. We've kind of figured out how this wet-and-dry cycle can be managed in these types of systems. We're starting to really get this thing down, and it's easily replicated by the patient aquarist. We have a lot of blog posts and podcasts about the process, and we've even developed a line of substrates just for these types of systems!

However, let's think about simulating the "inundation season" as the aquarium. Let's assume that you're kind of not into doing the whole "start with a dry habitat, plant some grasses and terrestrial plants, and gradually inundate it with water, then gradually dry it out again" thing that is the crux  "Urban Igapo" idea.

So, if you're going "straight to the inundation phase" of the habitat in your tank, you can still take the approach of replicating the dry forest floor before adding  water. to the aquarium.  


By regularly wetting these materials- the substrate, leaves, botanicals, and wood- down for a few days, and letting them saturate, it's entirely possible to go from "terrestrial" to "aquatic" in a very short period of time, and getting the cool effect- and indeed, part the function (a burst of microbial life, biofilms, fungal growths, and release of tannin and humic substances) of this system from the start. 

At the risk of sounding crassly commercial, I'd recommend some sort of bacterial inoculant, such as our spray- on Purple Non-Sulphur Bacteria inoculant, "Nurture".-to "kick start" the biological processes in your system before it's inundated with water.


I think that this step of "bacterial inoculation" is such a fundamental part of the botanical-style aquarium approach. I see it as much less of a "hack" to kick-start the nitritogen cycle (it will help do that...) and more of a way to provide an initial population of life forms which help assimilate some of the botanical materials and make the many organic (and other) compounds and substances locked in their tissues (tannins, humic substances, lignin, sugars, etc.) available to other life forms within the evolving microcosm you're creating.

This type of "terrestrial first" approach to starting a "flooded forest"-themed aquarium is very interesting from so many standpoints. And, it gives you an interesting way to really experience the processes which occur as terrestrial habitats transform into aquatic ones.

And, from a strictly "practical" point of view, preparing the aquatic habitat in a terrestrial phase before filling it with water is not all that different from the approach many serious aquatic plant hobbyists take when setting up their systems, right?

The main difference are is that, unlike our planted tank friends, we're more interested in setting up a "whole habitat simulation", as opposed to just setting the stage for aquatic plant growth, and we're likely not adding fertilizers to our substrate of choice. Rather, we're more interested in fostering the development of microbial and other life forms throughout the system once water is added.

I suppose another good analogy might be the approach that our vivarium friends take when creating "bioactive" substrates for their frog enclosures and such. The idea being to cultivate as large a population of beneficial organisms in your aquarium as possible from the start, to deal with the significant bio load that a large quantity of botanical materials brings.

Now, from a purely functional standpoint, you can replicate many aspects of the flooded forests by taking this approach. And of course, you don't have to go batshit crazy trying to replicate every single aspect of these habitats in your tanks. I mean, you could. Really, though- all sorts of fun variations are possible. Remember, it's not about trying to please some contest judge with an absolutely perfect biotopic representation, or a "ratio-compliant" aquascape. 



It's about experimentation; studying, observing, and replicating a natural process in the the best of our capabilities. "Artistic liberties" are not only possible- they're welcome!  So many iterations, interpretations, and experiments are possible here.

So, what's this all mean? What are the implications for this practice in our aquariums? 

I think it means that we need to continue to foster the biological diversity of animals in our aquariums- embracing life at all levels- from bacteria to fungi to crustaceans to worms, and ultimately, our fishes...All forming the basis of a closed ecosystem, and perhaps a "food web" of sorts for our little aquatic microcosms. And one way to help foster that is perhaps most enjoyably facilitated through this sort of "terrestrial first" approach!

It's a very interesting  concept- a fascinating field for research for aquarists, and we all have the opportunity to participate in this on a most intimate level by simply observing what's happening in our aquariums every day!

Fostering a diversity of life forms in our aquariums is interesting enough, but when you factor in seasonal changes and cycles, it becomes an almost "foundational" component for a new way of running our botanical-style aquariums.

It all starts with an idea...and a little bit of a "waiting game..." Patience. And a belief in Nature; a trust in the natural processes which have guided our planet and its life forms for eons. 

The appreciation of this process is a victory, in and of itself, isn't it? The journey- the process- is every bit as enjoyable as the destination, I should think.

It's all out there for us to learn. Investigating the relationship between land and water might just lead to a new world of discovery for the hobby.

Stay adventurous. Stay curious. Stay creative. Stay observant. Stay undaunted...

And Stay Wet.


Scott Fellman

Tannin Aquatics.

Scott Fellman
Scott Fellman


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