I would like to add a fish to my tank but have no idea what to buy. I have a 55g tank with a JD ( I think female), a blk convict ( I think male) and a Pleco. I would like something with lots of color and personality. But they need to be able to hold their own. My convict is kind of bossy but for the most part is harmless. They are both around 2.5-3'inches. Any suggestions?