So thats like a 45 (US) Gallon? When keeping most CA/SA Cichlids the problem is the length and width of the aquarium. I would pick something that doesn't get too big and keep the water in great condition. This will allow it to thrive. You could do a Salvini, Severum, or Convict. Personally, I would advise doing something like a pair of Angelfish, Discus, or Convicts in an aquarium with those dimensions.