When it rains...the "365 dynamic aquatic display" revisited...

"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...

Off to a great start, I think!

One of the most essential and life-giving processes of our planet is weather. And one of the most important components of weather 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. 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 smart ass, okay? :)

Well, what happens in the "rainy season" in say, the Amazon Basin?

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, for example- 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; often, currents re-distribute this material into little pockets and "stands", affecting the (now underwater) "topography" of the landscape. 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. Biofilms form, crustaceans multiply rapidly.  Fishes are able to find new food sources; new hiding places..new 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, "codependent" sort of arrangement!

And 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. 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 Paulie Dema of Vivariums in the Mist in New York has used to create some amazing setups, some incorporating our botanicals! 

Think about the possibilities here. As the display "floods", the materials in the formerly "terrestrial" environment become submerged- as in nature- releasing nutrients, humic substances, and tannins, creating a rich, dynamic habitat for fishes.

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

Now, I have no illusions about this being a rather labor-intensive process, but it's not necessary to make it complicated or difficult. It requires 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!

Sure, 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...

The possibilities for education, creative expression, and experimentation are really wide open here.

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 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- biotope "operation!" The idea of a "365 Dynamic Aquatic Display" has never been more approachable!

I'm just gonna 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.

Stay creative. Stay excited. Stay imaginative. Stay relentless...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

Scott Fellman
Scott Fellman


4 Responses

Scott Fellman
Scott Fellman

January 30, 2018

HI Justin- thanks for the kind words!

I love the idea of an ephemeral grassland biotope. I will have to do a “deep dive” into the concept/execution of such a display very soon. I think this is yet another way to employ “functional aesthetics” in managing a biotope system- utilizing technique to create not only an interesting-looking tank, but to manage the system via manipulation of the “seasons”, etc. I personally believe this is the next “frontier” for biotope aquariums. Yeah, I’ll have lots more to say on this stuff soon!



January 29, 2018

Love your musings. I have been wanting to do an ephemeral vernal pool or wetland type aquarium for awhile now, and glad I’m not the only one who thinks this is a great idea. Would love to hear your thoughts and ideas on creating a pampas grassland ephemeral wetland with a dry and wet season for killifish.

Scott Fellman
Scott Fellman

January 25, 2018

Good thoughts on the varying water level…to get that “intertidal” thing (which would work awesome in a brackish tank, BTW) would require use of an auto top off or other kind of dosing pump…or perhaps some sort of plumbing (like a valve which opens to drain the water slowly at a specific time..). I think such a system would eliminate, for example, a wet/dry or other system which requires an overflow weir. Likely, a system which draws from below the surface (i.e.; a canister) would be the call here. I know some people in the reef world who played with the concept some time back…I’ll have to follow up on this!



January 24, 2018

I always find these elaborate concepts of yours the most interesting, because I feel like aquarists have been conditioned to fear change within their systems for the most part – a deviation in consistent parameters means that something is wrong!

I think that many of us do have to deal with these seasonal changes though. For instance, in our house the temperature can range from 16*C at night in the winter up to 30*C+ in the summer! While I try to keep my temperate tank at a reasonable 18*-20*C with a small heater, the rising temperatures are surely felt even in the warmest of tropical tanks! This has induced spawning among my minnows, an increased appetite among my inverts, and a growth spurt for some of my plants. And of course a water change (or absence thereof) will cause a mild shift in nutrient and mineral content, tannins, salinity (should this be brackish) and other factors in even the most carefully moderated system.

Taking these seasonal changes a step further with water level management, flow, and all of that other good stuff is fascinating, but will no doubt require more engagement by the hobbyist as well, as well as the use of equipment that might need to be invented! (Is there a filter system that will discretely support dramatic shifts in water level?) Fascinating stuff, I’d be interested to know if there are any hobbyists working on this!

Leave a comment