Keeping and breeding silver dollar fish?

i have 6 young silver dollar fish, all bought between 1 yr and 6 mths ago. 2 of them are now obviously adolescent males and are beginning to come into colour and chase each other around the tank. I have 2 that are defiantly female and sometimes one of the males does exhibit mating behaviour toward them. my question is... will I have to get rid of one of the males or will they learn to live peaceful together. I thought they were shoaling fish and lived together in groups. My tank is 4 ft and they share it with a small group of clown loaches, small shoal of lemon tetra and small shoal of zebra deno, plus one bristle nose catfish.