convicts, large oscars, exodons, pleco and bottom dwellers. It's not guaranteed but they will eventually die probably. You may as well just get another piranha.
you should also try to upgrade to a 75 so you can have the footprint you need for them to live in there for life but there is no fish except for maybe a pleco that u can keep if you give them plenty of hiding space
[/IMG]my cousin has eight rbp he mixed many fish with them successfully. jack dempsy,oscar, buttfi. they all dominated the tank. he mixed them one at a time and ended takeing them out because they were beating up the pirahna. the oscar did the best with them he was dominat with out being mean. the dempsy & buttif were just plain mean. he tryed a wolf fish, blue lobster, red lobster, and crayfish. they all got eatenthe two lobster were pretty big