i have 4 yellow labs but im unsure to tell male from females.... one is got a black stripe on top fin and bottom fins are black, one has no stripes at all, then another has black stripe on top fin, and a tinge of black on bottom fins, then there is another that has black stripe on top fin and bottom fins have a shade of black in them as well...i can take pics and post if that helps as well .. ?? heard these guys breed like rats lol.... would like them to breed as well for live food