I have a 55 gallon tank and I want to stock south/central America cichlids/cichlid (willing to keep a solo fish). I have another 55 with a green terror pair, a 90 gallon with a zebra tilapia (buttikoferi tilapia) and now I want to add something to my empty 55. I don't want a fish tat will out grow the tank, maybe something maxing at 7-8inches. Also I wanted to stray away from common fish like convicts, jack Dempsey and firemouths. I was deciding between pike cichlids, severum, geophagus....but are there any other fish good for a 55?