I've kepts severeal different tropical fish species among them Pirahna-both Nattereri and Caribe- some several Cichlid species, Salt water Fish and currently Flower Horn and it is Flower horn what I find most rewarding of them all.
I dont think I can keep other than FH in the Future, i like Managuense but if I get a Managuense it would be keeping it besides FH, I dont think I'll be quiting the FH hobby, lol!