i have a 48 gallon bow front tank that is soon to be empty. i have one african cichlid in there right now, and a bala shark. The african is sick and i doubt will live much longer, i think the bala has been picking on him. i want to put in a serra of some sort (once the others have died), but worry that the tank may be too small. don't want to upgrade for at least a year. what should i do?????