Actually the bullheads are not causing any problem when I catch them they are 1/2-2lbs. I think the bass and other fish keep them from taking over so far but I wish I had not put them in. When I do catch them I throw them out. I am happy with the rest of the fish as long a the crappie do not get out of control. My ponds are 1 acre (mainly has bluegill, red ear sunfish and small bass) and the other one is 3 1/2 acre.