i personaly keep females in one coloney and males in other colloneys have 30 breeding females and 10 studds but once i start breeding i thow 2 femels per male in a tub for a week move male out for 2 days of rest and once females are close to birth i seperat them into there own tubs and give females a feeder fish that almost instantly brings them back up to waight. once the pups reach 4 weeks and i can see they are all eating on there own i seperat them into tubs keep some females not usually no males. i crush the lab diet up for the younger pups they seem to have a hard time pulling it threw the top. by using the feeder fish my females have had littlers of 15+ all live and they seem to grow faster this way as well. so it is worth the 2 pennys i pay. i havent been able to breed the feeder fish so if any1 can help i would apricieat it.