I have read that they are sterile, but on a forum somewhere (maybe this one) I read someone's Glofish reproduced and they have 100's of fry. So do they or don't they? If they do I'd like to consider breeding them. They are $8 ea. in my area. I plan to get a 10 gallon soon just for glofish, but they are so expensive I wouldn't pass up the chance to breed them for myself and maybe make a little $ to offset the expense of my hobby.