5-6 inch and non-aggressive.... if you don't care about mixing south/centrals with africans (not african lake cichlids), then I would go with Pelmatochromis Nigrofasciatus. It is a west african that gets about 6 inches, but could care less about other fish. It is not too common in the hobby, but it is available from time to time. I got mine from Tony Orso a few years back. Unfortunately I had to get rid of them (and my other fish), when I had a flood last winter.