You can keep 1 individual female but if you want more of a community tank the general # to keep is 5-6 so the aggression is spread out. If you only have 2 or 3, the dominant ones will gang up on the other and bully it. You also have to have lots of tall plants and caves so they can hide from each other when they need a moment. (You know how girlies need their ''private time.'' )