To my knowledge...males can only be housed together when they are father and son and aren't seperated from spawning into adulthood. The male keeps the fry in check and by the time they are adults they see their father as the dominant fish and won't fight him.
Who am I? Well I am a Junior Member of the International Betta Congress and a breeder of white HMPKs, red dragon HMPKs, black/red dragon HMPKs, metallic multi HMPKs, blue masked HMPKs, and now multi color HMs. Soon to add black HMs. I will be showing in New Breeder class in fall of 2012.