I have 3 - 2 of which are bright yellow and the third has dark stripes down iit's side. When I got them I thought they were two females and one male, but now that they are mature, I reckon I've got 3 males. Unfortunately I haven't got room in the tank for any females, but they don't seem to fight a lot, maybe coz they grew up togher. ANyway, I've no idea why one has stripes - it eats the same as the others.