cichlid fighting

hello I have a yellow lab and I just got a blue one that looks just like the yellow lab but .5 inch bigger. My yellow Cichlid was aggressive to the catfish and took chunks out of his fins but now the blue one is terrorizing the lab. I heard I could get more to get rid of aggression but I have a...

I recently got two small convict cichlids. The male is always attacking the female, and she has some small bite marks on her tail. The person at the pet store told me the male was trying to breed with the female, but I found it strange that he would bite her fins. :( Help please!!!