It all starts with rain...


As aquarium people, we are obsessed with water. Of course, it's fundamental to what we do. We are fascinated by its characteristics and life-giving properties. And of course, we take it for granted, like so many things. Perhaps not like the non-hobbyists, to whom if you ask, "Where does your water come from?", you're likely to hear an answer like, "Duhhh...from the faucet!"

Nonetheless, we as hobbyists also probably don't give it a ton of thought in the grander scheme of things. I think that, on occasion, we as lovers of truly natural-style aquariums owe it to ourselves and our fishes to consider- occasionally- how water arrives in the wild aquatic habitats of the world and its role in shaping them.

Of course, it starts with rain...

One of the most essential and life-giving processes of our planet is rain. 

Rain is truly the bearer of life.

It's transformational, essential for our existence...and for the continued existence of many of the fishes we love, as well as the habitats from which they come.

And specifically, what interests me about rain is what happens when it rains in the wild habitats of our fishes, and how they behave. How do their habitats change with the coming and going of the rains?  What happens to the fishes during the rainy season?

I know, you're gonna say, "They get wet..." 

Look, no one likes a smartass, okay? 😆

Well, what happens in the "rainy season" in say, the Amazon Basin? (like, why did you know that I'd start there? Hmm?)

A lot of things, really.

The wet season in The Amazon runs from November to June. And it rains almost every day. And what's really interesting is that the surrounding Amazon rain forest is estimated by some scientists to create as much as 50% of its own precipitation! It does this via the humidity present in the forest itself, from the water vapor present on plant leaves- which contributes to the formation of rain clouds.

Yeah, trees in the Amazon release enough moisture through photosynthesis to create low-level clouds and literally generate rain, according to a recent study published in the Proceedings of the National Academy of Sciences (U.S.)!

That's crazy.

But it makes a lot of sense, right?

That's a cool cocktail party sound bite and all, but what happens to the (aquatic) environment in which our fishes live in when it rains?

Well, for one thing, rain performs the dual function of diluting organics, while transporting more nutrient and materials across the ecosystem. What happens in many of the regions of Amazonia is the evolution of our most compelling environmental niches: 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. 

All of the botanical material- fallen leaves, branches, seed pods, and such, is suddenly submerged. And of course, currents re-distribute this material into little pockets and "stands", affecting the (now underwater) "topography" of the landscape. Leaves begin to accumulate. Tree branches tumble along the substrate  Soils dissolve their chemical constituents, tannins, and humic acids into the water, enriching it. Fungi and micororganisms begin to multiply, feed on and break down the materials. Biofilms form, crustaceans reproduce rapidly.  Fishes are able to find new food sources; new hiding areas to spawn.

Life flourishes.

So, yeah, the rains have a huge impact on tropical aquatic ecosystems. And 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.

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

And of course, I think we can work with this stuff to our fishes' advantage!

We've talked about the idea of "flooding" a vivarium setup designed to replicate an Amazonian forest before. You know, 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. Just check out our friend, Paul Dema's Vivariums in The Mist website for some prime examples..

The time to play with this concept is now!

Sure, you'd need to create a technical means or set of procedures to gradually flood your "rainforest floor" in your tank, which could be accomplished manually, by simply pouring water into the vivarium over a series of days; or automatically, with solenoids controlling valves from a reservoir beneath the setup, or perhaps employing the "rain heads" that frog and herp people use in their systems. This is all very achievable, even for hobbyists like me with limited "DIY" skills.

You just have to innovate, and be willing to do a little busy work.

Or, you can purchase an off-the-shelf product like the Biopod, which our friend Paul has used to create some amazing setups, some incorporating our botanicals! 

Think about the possibilities here! It's crazy!

As the display "floods", the materials in the formerly "terrestrial" environment become submerged- just like in nature- releasing nutrients, humic substances, and tannins, creating a rich, dynamic habitat for fishes, offering many of the same benefits as you'd expect from the wild environment.

Recreating a "365 dynamic" environment in an aquatic feature would perhaps be the ultimate expression of a  biotope aquarium- Truly mimicking the composition, aesthetics- and function of the natural habitat. A truly realistic representation of the wild, on a level previously not possible.

Of course, I have no illusions about this being a rather labor-intensive process, brought with a few technical challenges- but it's not necessary to make it complicated or difficult. It does require some "active management", planning, and diligence- but on the surface, executing seems no more difficult than with some of the other aquatic systems we dabble with! (Like, hello- my reef tanks, for example!)

Yes, you'd have to make some provisions for "relocating" the terrestrial inhabitants of your system, like frogs, to "higher ground" (i.e.; another vivarium) during the "wet season"...or your could create a paludarium-type setup, with both a terrestrial and an aquatic component simultaneously, and not sweat it.

The possibilities for education, creative expression, and flat-out experimentation are really wide open here. A great way to examine and appreciate the cycle of life for many organisms!

One could mimic all sorts of geographic locales, including Africa and Southeast Asia. Annual killifish would be another beneficiary of such a process/system, with the ability to literally "desiccate" their environment for the "dry season", and flood it once again when "the rainy season" returns!

We kind of do it already with the old "peat moss in a bag" trick to incubate their eggs...this is just a more interesting (and probably a bit more tedious/less efficient) way to do it...but one which may yield some interesting insights into their natural habitats!

There are so many possibilities here...Well- it literally could create an entirely new "sub-hobby" within the aquatic hobby...not just biotope replication- I'm thinking biotope "operation!" The idea of a  truly dynamic aquatic display has never been more approachable!

Okay, I'm just going stop here, because I could easily go on and on and on....

Think about it. Build it. Play with it. Learn from it. Share it.

It all starts with looking at the natural environment, and considering the role that rain plays in this dynamic- then figuring out how to incorporate it in to our aquariums...

"I'm only happy when it rains
I'm only happy when it's complicated
And though I know you can't appreciate it
I'm only happy when it rains..."

- From the song, "I'm Only Happens When it Rains" by Garbage, 1993

Yeah, rain is cool!

And today's topic allowed me to quote lyrics from an obscure, yet satyrical post-punk song from one of the better bands of the 90's! 

Does it get any better? I don't think so. 

It all starts with rain.

Stay dynamic. Stay creative. Stay inquisitive. Stay imaginative. Stay inspired. Stay relentless...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


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