A female will definately raise the aggerssion levels of the males, I got rid of what I thought was my only female peacock, my 5" Regal was going after everyone, even a front twice his size. Well turns out I had another female in the tank, I left my lights off for 2 days, when I turned them back on to my suprise one of my smaller peacocks (thought to be a male because it had some color in it) was holding! Since then the aggression has gone down again. If I were you I'd stick with all males.