Thanks for this thread. I just acquired 2 - 30 gallon tanks, fish and all, for free. Am having trouble ID'ng all the fish, 22 in all. Well, thanks to this thread, I now know that I have 2 convicts. As for sex, I have no clue if they are a mated pair or not. They are small. How big do they get??? Beautiful fish, and nice pics by all.