Its a chance you might win, but be prepared to seperate them if it doesn't work out. I added a much smaller one to my tank and my female was having none of it. She tore into the little guy with a vengence, ripping fins and biting. The new guy would surely have been killed if I didn't remove him. Even after taking the new one out, my female searched the tank for hrs trying to find him, and she usually stays on one side of the tank.