As they get older, yes they may develop more black. Not all are the same patterns though. As far as 3 clowns, like stated above, not a good idea. One will end of dead with the others injured. Never good. Once they become more mature, it will be the largest that will become female, the males will then fight. The female will also become aggressive at first to both males. Two is much more simple. They should pair after a few scuffles and thatll be it. 3 will prolong that process, complicate things, and sadly cause a never ending fight.