oddballs and catfish can live with cichldis easily, i mean in my tank i have bichirs and a hujeta gar, and there fine, not to mention a plec and a syno.
rainbows will mostly breed in groups if you dont wish your fish to breed its probably easier to get one of each...
Catfish, yes, but he said corys. The problem with corys is that they are totally stupid about territorial boundaries. Being themselves happiest when piled on top of each other in a great communal embrace like pigs in a stye, they do not understand the concept of personal space. They also cannot stand up to aggression. Hence the difficulties with keeping them with any fish that is going to regard part of the bottom level of the tank as their territory.
Plecs or synos would work a lot better, being tougher and having more spatial sense.
