There's alot of cichlids you could house with that tank, a pair of Salvini's would be cool, convicts or honduran red points, green terror, rainbows, or firemouths. Or the fish from the Rift Valley, some dwarf mbuna or brichardi would also work well. Just try and stick with something in the 6-8" range, stay away from the big boys until a six foot tank comes about.