still look like females. I have a male that is about 2.5" and the only indication is the dorsal and anal fins are starting to develop points. I have had the fish for several months now since he was about 2" and the fins were starting to already to develop at that size.
male. Sometimes I can faintly see some orange/maroon on his sides. I chose him from the tank at the LFS because he had the most pointed fins and was one of the more aggressive fish in the tank. He also was kind of jet black and has remained so for the most part. The females usually seem to be more silver though this is not necessarily a reliable way to sex them.