I have bred cory cats, and it was easy. And it wasn't even on purpose. I had them in a fairly heavily planted 15 gallon and fine gravel substrate. The temp is 78-80 and the PH is 7.2 or 7.4 I think. I only had two of them, yet they bred and the eggs hatched. They have spawned probably 5 or 6 times. I actually just took them to a pet shop today because they bred too much (and I needed room for the babies to grow up). The last spawn was huge. There were eggs all over the glass, on plants, and on a shell I have in the bottom. If you keep any other fish with them they will more likely than not eat the eggs, so be careful about that. Good luck!!