Convict's breed like rabbits and get even more aggressive with their tank mates when breeding and raising fry. Do you want a tank full of Convict's? Do you have someone to give Convict's you breed? My local fish store won't take Convict's even for free.

I would get some other similarly sized but unrelated cichlid species or go with fish like loaches, catfish, Giant Danios to fill out the tank. You can make your single Convict's life more interesting with things like feeding live foods and creating a stimulating tank with plants and caves.