I agree with squidward, having mbuna or open water malawisis pushing it in a tank that size.
have a look at smaller tanganyikan cichlids
neolamprologus brichardi, neolamprologus leleupi, neolamprologus caudopunctatus, neolamprologus multifasciatus, neolamprologus brevis, lamprologus ocellatus and are all really nice little tanganyikans!