I've bred bronze, albino and sterbai corys, I tried for a year on the second try and got nothing.. As soon as I gave up a little hope, I got eggs. My heater actually broke a few days before they set off, I got a new one but the water temperature was fine at room temperature, so it was a bit cooler than normal.. Around 22-24C, I tried ice cubes etc before, it never worked for me. I collected the eggs with my fingers, very gently and put them into a breeder net so not to change the ppms and temperature. I feed mine a mix of algae wafers, catfish pellets and bloodworms now and then, they were a few years old when they began to breed. Just so you know, the fertilised ones go a tan colour, I always got told conflicting info on that one, the clear ones are not fertilised.