I'll bite since no one has responded. You can try all of them together while young, as they mature you will have all out war w/ the males who will want to claim a HUGE territory. Females are aggressive too, so down the road you may have one fish to a tank, so that would mean you would need 6 tanks. If you do get a pair remove all other fish from the tank they are murders when breeding. Fasciatus shows very little sexual dimorphism especially when young. Are you sure they are going to be fasciatus as they are pretty rare in the hobby, much more common available in the hobby is H. elongatus? Hope this helps.