so i have 1 oscar in a 46 gallon bowfront. I know its small but its just him in there. I do 25 percent weekly water changes and have a marineland 350 biowheel running and have a marineland biowheel 150. I had a blue crayfish in there but my oscar tried to eat him and in turn, the crayfish tried to eat my oscar lol, and scratched him all up. so any advice on smaller but good tank mate sicne i have a small tank, and waht to do about his scratches? thanks everyone.