Spawning Report: Corydoras sp. CW097

Submitted by Matt Chambers

Background: I purchased a group of these fish at a PVAS auction. The parents of the fish I bought had been collected by Don Kinyon in Peru. Don, as usual, quickly got the parents to spawn and started putting bags of the juveniles in PVAS auctions.

CW097 is an aeneus-type Corydoras, in Lineage 7 of the new classification of Corydoradinae. It is a typically sized Corydoras, with a gold bar or flash over its right shoulder.

General Care: I put the first bag of fish in a 12 gallon cube with a sponge filter. I fed them the usual variety of small pellets, flakes, Repashy Igapo Explorer, and occasional live food and waited for them to grow. They were healthy and active and grew quickly. Having said that, I was disappointed when I didn't see any spawning activity as they reached adult size. I tried doing the usual Corydoras tricks, particularly large cold water changes, sometimes using rainwater. Nothing seemed to trigger spawning activity

A few months later, at another PVAS auction, I bought a second bag of the same fish, hoping to get something going. It didn't do any good. The fish were still healthy, but I never saw eggs or even any sign of spawning activity.

Spawning! Finally, in the middle of January 2020, I added a powerhead to the tank. I was a little worried that the flow would be too great for the fish in such a small tank, but they seemed to find places to rest from swimming in the current. Three days later, I found about 80 eggs on the glass! The water was fairly soft, due to the use of rainwater, about 100 ppm of hardness, and cool, around 70F. I didn't check pH, but I'd guess it was somewhere between 6 and 7,

I moved the eggs to a shallow plastic container, with an alder cone and a small Ramshorn snail to prevent fungus. After four or five days, about half the eggs hatched. After a day or two, I started to feed them the smallest size of Golden Pearls and also banana worms. After about a week, I moved them into a Marina breeder box. Rather than set the box up as intended so that water from the tank dripped into the box and the outflow went back into the tank, I put about an inch of sand in the bottom of the box and then an inch of water, and put the body of the box in the tank, with an air stone. Every day, I changed out about one third of the water, re-filling with water from the tank, gradually making the depth in the box higher. The fry seemed quite healthy and were feeding actively.

After another week, I felt like they had grown enough to have no trouble with the deeper water in a full Marina breeder box. I carefully took the box out of the tank and installed it so that the water dripped into the box and then the outflow went back into the tank. The fry handled the transition well. They are still very small, but seem to be healthy and growing.