whats the best ratio for breeding

[Cichlid_beast123]

i have a colony of dolphins 11 i heard some people go for 18 fish in a 500 l tank 3 kinds i might do that too but ill have to remove the males too many maybe 1 alfa who did breed once but she spat out 4 days later then one beta those 2 are the large ones then it turns out defo 3 medium sized males chasing females about oh and 2 juveniles so that is 4 females only what are your thoughts should i remove the other males?

[IanG]

Dolphins are not particularly agressive in fact for malawis they are docile. There is normally sparring between males but vet little damaging aggression. I would remove dominant male and see if situation improves. Then if aggression goes away try reintroducing a few weeks later and he may then behave