Ok thanks very much for your help! Will it harm the eggs if I add a heater now? When do I need todo my first water change after they have hatched?
I don't know about the heater as I never added one, but just keep an eye on the water quality. I changed mine when I couldn't keep up with the layer of "scum" on the surface of the water. I would siphon it off with a turkey baster but at one point for me it became too much. The easiest way to do a water change is to go to Walmart and get a couple of white sterilite dish pans. One for the fish to be in and one with clean water all ready to go so you dont have to worry about matching temp, ph, etc.
My advice is to read lots of fry threads! I got a lot of information from them last spring when I had eggs