As the seasons change...

As we ease into the Fall here in the Northern Hemisphere, it's easy to contemplate the subtle- and not so subtle- things that occur when the seasons change. And of course, I can't help but wonder how this affects our fishes.

I mean, it's obvious how it affects our hobby efforts. With cooler weather prevailing in many parts of the world, and outdoor activities starting to become a bit less attractive in some areas, many hobbyists once again turn their focus on to their aquariums. Many are focused more on perhaps starting-or finishing-projects which previously were delayed in favor more appealing summer activities. Yes- it's "Aquarium Season" here in the Northern Hemisphere!

Now, all seasonal celebrations aside, what kinds of impacts do seasonal changes have on aquariums and the fishes which inhabit them? Well, for one thing, lighting differs. Since many of the areas from which our fishes hail are near the Equator, there is very little temperature variation between the seasons. However, the rainy season in these areas does occur, and impacts the aquatic habitats significantly.

In the Amazon, for  the wettest part of the wet season occurs between December and May. During the wet season, the Amazon rainforest receives as much as 6 to 12 feet of rain (1.98- 3.6m), which can cause rivers like the Amazon to rise as much as 40 feet (12m), flooding the surrounding forest areas. The fishes adapt by moving into these areas that were previously barren and dry, foraging among the now-submerged trees, grasses, and plants.

Everything seems to adapt in the rain forest, including even the trees. Trees have adapted to this seasonal flooding by developing roots that grow above the ground. These roots are known as "buttress roots." They would be an interesting feature to replicate in the aquarium, right? And interestingly, recent studies have shown that rainforest trees and plants actually "flush" (grow new leaves) shortly before the arrival of the dry season. It's postulated that there is something in their genetic programming that allows them to prepare for the onset of the relatively "light-rich" dry season, to get them ready for  enhanced photosynthetic activity. Even the dry season could be replicated in an interesting manner!

So, how do we sort of mimic the environmental effects of this seasonal inundation in aquariums? Well, short of running them half-full most of the year, and then increasing the water level to full during the "rainy season" (ohh...that's a cool idea!), perhaps we could mimic the dilution which occurs when massive amounts of rain fall. In other words, lots and lots of water changes! Like, maybe a few times week in greater percentages.

"Fellman, you're insane! The benefits that you'd get from all this extra work aren't worth it."

Do you know that for sure? I think it's a worthwhile experiment.  :)

Of course, other things you could do to mimic this seasonal inundation are to add more and more leaves and botanicals during this time, mimicking the affects of continuous leaf drop and the accumulation of botanical materials caused by currents. And perhaps even "refreshing" the substrate with additional material (like soils, know, that planted aquarium stuff) to sort of simulate the release of new organics and other compounds caused when previously dry forest floors are inundated with water.

Oh, and a lot more food. Like, feed a lot of live food like Daphnia, copepods, worms, fruit flies, etc. Stuff that would likely be more readily available to fishes in an inundated environment. Perhaps even changing the diet seasonally to reflect this abundance would be interesting. Now, I"m not suggesting to starve your fishes the rest of the year, but I am curious if there would be any significant effects that we'd notice in captivity by varying the diet based on seasonal availability of different food sources...I mean, fishes have evolved over the eons to feed in this manner...could it be a key to better breeding, perhaps activating some locked-up genetic programming in even our captive-bred cichlids, characins, and catfishes? Who knows?

There are many, many different seasonal "change cues" and occurrences which we as hobbyists can study and experiment with to see what, if any impact they might have on the fishes we keep. The adaptations and behavior changes which occur in our fishes which stimulate spawning and such might very well be tied into these seasonal changes, and perhaps the key to more predictable/successful spawning of challenging or previously "un-spawnable" fishes could be replicating them, to some extent, in our aquariums.

Something to think about. Something to play with as the days grow colder, the nights grow longer, and the opportunity to spend more time in our fish rooms beckon.

What secrets will YOU unlock? What lessons will we learn? What fishes will we spawn?

Stay bold. Stay innovative. Stay adventurous. Stay diligent. Stay experimental.

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Scott Fellman
Scott Fellman


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