By Don Kinyon
An attractive Corydoras from the rivers of Suriname and Guyana, CW114 has been proven to be a color variety of Corydoras sipaliwini (Hoedeman, 1965). Very little information seems to be published on this particular fish, but if we assume the native conditions are similar to other Corydoras species of the region, it comes from slow flowing areas of the river and from fairly soft, acidic waters.
With information as scarce as it is on these fish, we’ll have to use my few adults for some of the description. They seem to be a mid-sized Corydoras with the males reaching around 1 ¾” and the females a little larger and heavier-bodied. The coloration of the species is subdued, but not unpleasing. The base body color is a light bronze, and all markings are black. The markings vary from fish to fish, but all have some traits in common. Spots and mottling on the head transition to elongated spots on the upper half of the body that follow the seams in the armor plates. There is a black stripe that begins about mid-body behind the pectoral fins and continues to the tail. There are sketchy vertical stripes on the tail as well. Except for the first one or two rays of the dorsal fin, the rest of the fins are clear.
Always on the watch for species of Corydoras that are not common in the hobby, I jumped at the chance to purchase this species when they came up on one of the importer’s availability list. When I called, they only had nine left, so I ordered the lot of them. When the fish arrived, all but one looked to be healthy and active, and even the one didn’t look too bad considering the trauma of shipping. The fish were around one inch when they arrived, so we can assume they were still fairly young.
The new arrivals first home was a home built tank of about 15 gallons, starting out with ½ tap water and ½ rain water, putting the pH near neutral and TDS at 90 PPM. The tank was unheated and stayed in the low to mid 70s. There was a Mattenfilter on one end of the aquarium with two uplift tubes for circulation. Some fine sand covered the bottom at a depth of around ¼” and a few round stones and small pieces of sunken wood finished the decor.
The first two weeks proved to be difficult for both fish and fishkeeper. Two days after the fish arrived, the one that looked a bit haggard at arrival passed away. Two days later; another, then another. By the end of the first two weeks I was down to five fish and confused as to what I was doing wrong. I’d worked with this importer many times before and they’d always been top notch, the fish didn’t seem stressed, and the water conditions all checked as good- almost perfect, in fact!
To this day, I still don’t know what the reason was for the die-off. It stopped at that point and the rest of the group survived. Once the young Catfish started to grow and mature, it was evident that I had two males and three females: not perfect for a breeding group of Corys, but much better that it could’ve been. The group was fed a great variety of foods: a few different brands of flake food, frozen blood worms, frozen black worms, Repashy gel foods, live blackworms, and pelleted foods.
After around eight months, there appeared an egg on the foam filter. It must have been there a few days before I noticed, as it was already white and showing filaments of fungus- a bad egg, but an egg all the same! To give the fish more suitable areas to place the eggs, I added a floating yarn mop and a bottom mop, and from this point on kept a closer eye on the tank.
A few days later, I was rewarded with 5 more eggs, most on the floating mop, but one on the bottom mop and one more on the filter foam. These were placed into a smaller tank, about 5 gallons, with water from the breeding tank. A small alder cone was added to the tank to discourage fungus from spreading. In two days, it was clear that the eggs were bad and not going to hatch. In about a week, more eggs could be seen on the mops and on the filter, and this time there were a few on the glass as well. They were all removed and treated the same way, with the same result- no hatch.
Frustrated but undeterred, I changed the water in the tank over to 100% rain water which brought the pH down to 6 and the TDS to near zero. More eggs, same treatment, same results, more frustration.
I don’t generally use artificial pH buffers and would much rather do things naturally even though it usually takes longer. A handful of oak leaves was added to the water to start decaying-vegetable-matter-black-water-environment. This was left for a few weeks and I didn’t bother to collect any eggs for that time. The tank still got weekly water changes at a rate of 25% with rain water, but otherwise the parameters were left to themselves.
When the pH was checked again, it was at 5.5 (according to my primitive eye dropper pH kit) and on inspection of the tank, there were more than a few eggs in all the same locations as before. I decided to collect the eggs and try once more, but as I removed the bottom mop, and few tiny fry scattered from underneath. When some of the leaf litter was moved around, more fry scattered. Once again, it seems that the fish do better with less interference from the fishkeeper.
After two more large bottom mops and a few more oak leaves were added, the bottom of the tank was completely covered, giving the fry ample places to hide. The fish were left to their own, except for feedings and weekly water changes. Micro worms, commercial fry foods and decapsulated brine shrimp eggs were added to the feedings in order to give the youngsters enough to eat. The spawning seemed to be almost constant: never a great number of eggs at once but a few in the mops, on the glass, or on the filter foam at any given time. “Flashlighting” the tank after the lights were off at night while pulling one of the mops from the bottom would show a group of fry from newly-hatched to young fish that were nearly 1/2” long and resembled the shape of their parents.
At this writing, many of the young fish have been removed to other aquariums to keep the breeding tank from being overcrowded (not any easy task with all the cover), and the adult fish are still producing eggs on almost a daily basis. I’m hoping that I can pass some of the young to other breeders and make this Corydoras a much more common fish in the hobby.