Bronze Corydoras Biotope 9669 4 x 6 Canvas Prints are available at Tanninaquatics.
By Ivan Mikolji / 2017
I am standing in the middle of the creek, motionless. The sky is blue with no clouds and the sun is shining brightly. A soft tropical breeze is swaying the tree canopy which seems over 20 meters above. Boy, the trees are tall in this place. I love the breeze, it sooths you from the scorching heat and kind of deters some of the flying hematophagous insects. The only downside is that the same breeze that keeps flying insects away, gets you filled with what I call, kamikaze insects. These insects which live way up high in the densely, vegetated tree branches are knocked off in large amounts by the breeze. Trust me, it is hard to stand still when you have a couple of unidentified insects walking on your neck or even worse when they start venturing into your ear. I swat the insects off and again assume my motionless position, just like a Queen’s guard, but in a wetsuit.
There are two prominent colors everywhere, green and brown. The water’s surface reflects the green from all the vegetation and because the water is clear you can see the brownish benthic sediments below, again adding more of the same to an incredibly beautiful bichrome world. The water is around a perfect 28 Celsius with a slow flow over rounded rocks of all sizes. This, my friends, is a typical Maritime Andes mountain stream. The Maritime Andes is the mountain range that runs along the mid and eastern coast of Venezuela.
So, I am still standing motionless in the middle of the creek. As usual, I am wearing my good ole trustworthy straw hat. I am placing all my bets that if I stay still enough, long enough, I will not look like a threat to the Bronze Corydoras Corydoras aeneus that live in this section of the river.
Corydoras aeneus are relatively small benthic armored catfish which are quite common in the aquarium hobby. Bronze Corys have the ability to breathe air intestinally, so in an aquarium you can see them swimming up to take a gulp of air from the surface and then heading immediately down, this air probably also aids them in their digestion.
I know from experience that fish will get used to my presence quite quickly, usually in about one to two hours. I have certain rituals which to a bystander would look sort of weird, but to me, deliver many benefits. As I stand motionless, I am deciphering the ecosystem surrounding me and I am also learning the behavior of the animals around me. Let me tell you what I am absorbing. Above, out of all the trees, the ones which I find to be the most majestic are the huge Rain Trees Albizia saman whose branches spread out like a humongous umbrella and are filled with large amounts of epiphyte plants. Below, the Astyanax metae tetras are hunting the large amount of kamikaze insects that fall in the water. Their speed is so fast that a quarter of their body comes out of the water as they dash to get to the food before somebody else snatches it. As they hit their target, they create a snapping sound which seems quite loud for such a small fish. When the breeze calms down, the water surface becomes silent and smooth, the tetras wait calmly. When the wind picks up, and the insects start falling again, the water surface starts bubbling and sounding unpredictably. Terrestrial insects must be a primary food source for so many fish in the wild.
The river itself can be broken down into the regular pools, flats, runs, and riffles structure. I am standing in a flat which seems about 100 meters long, 7 meters wide and 40 cm deep in the edges and about 20 cm deep towards the middle, yes, it is deeper at the edges. A river flat can be described as a long shallow pool with unbroken surface and a relatively smooth bottom. The pH is 7.5 and the KH is arround 40 MG/L.
Ok, and here comes a school of Bronze Corys, this is where they live. They are only found in the flats of this stream, they do not live in the pools, runs, or riffles. I am almost in the middle of the river facing the right bank of the river which is best lit up by the sun at this time of day. I try my best to stay still and mentally record what I see. The Corys are swimming upstream, I start counting them as fast as I can, but I loose count after 8, they are swimming too fast and there are too many of them. There are probably more or less 150 of them swimming nonstop in zig zags. As they zig zag in the water, in front of my feet, my mouth opens wide. The zig zag swimming pattern is completely intentional, they are swimming in the shade created by the branches of the canopy 20 meters above. As I stand there, looking at these fish shoaling through the intricate outlines and patterns the first thing that comes to my mind is the similarity of blood flowing through veins or cars riding on an insanely designed highway. It is incredible to see how they really do a great job of not steering off the road, even if the shadows are faint. I watch them, the long line of specimens go by, bumper to bumper, passing in front of my feet. Two meters upstream, to my left, is a sandy, rock less spot which is in the shade. Some of the Corys slow down and start swimming around, forming a circle. This behavior reminded me of what the wagons would do when attacked by the Indians in the old Wild West movies.
All of a sudden they all stop, they rest for about one or two minutes and then they turn on their motors and start heading upriver again through their shaded highways. I decide to stay put and wait for another school to come up. Not too long afterwards, a smaller school passes by following the same rules as the first batch of Corys, but as they get up and go from the wagon circle, they swim quickly across the river. They never swim in the middle of the river, but when they do cross it, they make sure to do it at full speed. I slowly turn around and watch them head down stream on the other deep bank on the left which is rockier and darker. That is the Cory return lane. In the left rocky and darker bank they take the time to feed off the periphyton that is stuck on the surface of the rocks.
In the crevices, between the larger rocks, leaves and twigs deposit over a dirty clay. The clay is filled with decaying organic matter, here they wiggle themselves into that gunk as if they were burying themselves underground, creating small clouds of flotsam. They resemble little piglets having fun in the grime probably digging up their next meal. So, this is their feeding ground. The sandy middle and sandy right bank seem to be too clean or sterile. The Corys in this stream use the clean sandy right side to head upstream and eat on the left rocky side as they go downstream. I wonder, why don’t they just go up and down on the left bank? I decide to stand still looking downstream so I can look at both sides at the same time; something bites my neck and as I squish what looks like a red ant, I see the Corys flee, scared from my sudden movement. I smile and laugh; standing still with my straw sombrero, I am a live fish scarecrow or better yet, a scarecory.
Now that I know the Corys behavior, flow of the water, where and how the light is lighting up the biotope, I start envisioning how I am going to digitalize them. I start elaborating a plan to capture each behavior.
Because I am who I am and I cannot get out of doing things the Mikolji way, I try to complicate the job and make it as complex as I can, take things to the limit in photography, set the standards way up there and make the next, new generation that will replace me sweat a bit more to surpass me. I toss my hat into the bank foliage and lie down in the water. I crawl towards the right bank over the fine gravel and look for a very shallow spot where my camera lens can be half in and half out of the water. I make sure that I get a spot where there are shadows near the lens and far from the lens as well so the Corys do not look in a long line or in a big dense group.
I want them spread out, following the shadows near the bank. I adjust the settings on my camera and wait motionless, sure enough, they pass by beautifully in front of the camera doing what they know how to do best, being a Cory. I follow the same steps in the open area and again they do the wonderful wagon circle for me, they are the best models to work with. I get up and do the left bank which has its complications because of the amount of dirt they stir up as they swim and feed, but hours of waiting patiently most of the time pays off.
Once the job is done I do my usual last ritual which is to put down the cameras and just lie there underwater pretending to be a fish and wishing time would just stand still.
This article has been published at:
- Practical Fishkeeping Magazine – February 2017