I would suggest a pair of Jack Dempseys. In my experience they tend to hold stronger pair bonds than a lot of other cichlids. On top of that, they are lurkers. So, they will find a home and spend most of their time there allowing you to have dithers and other fish in the tank without as much risk (although with cichlids, there is always some risk). One last plus is that they are very common and inexpensive but still have some of the best colors out there.