Ya tht would be better. Tk ur oscar and let him recover his life. Then i'd suggest u to remove ur convict, hv the oscar in & let him establish and then add the convict into the tank later. Also while the convict's out of the tank change the geography of the tank completely such tht the convict thinks ths is a new tank. Do hv a lot of territories. Broken flower pots'd be ideal. Then i think ths prob would be solved.