When I upgrade my knife tank I want to put a catfish in with him. He hasn't had a tankmate in about 8 months. He is about 18" and mild tempered. Could I put a tiger shovel nose in with him? I love shovel nose catfish and would love to have a large tsn in my big tank. Would it work out, or are they not compatible? I am shooting for my next tank to be 150 gallons. The knife tank right now is 90 gallons.