There are some fish farms that do raise bullheads. Although they are not a favored fish by most, some people do like them. I personally think they taste better than channel cats. However, they are much harder to manage as they readily reproduce in ponds and often stunt even with predation which CC don't do nearly as much. If you don't get a bunch of hungry bass into your pond soon, you will end up with piles of 4"-5" stunted bullheads, I can almost guarantee you that!
Catmandoo's recommendation of starting over is a smart one if you don't want to stock bass into the pond. If managed correctly, bullheads can grow to 12"-16" in size and produce good tasting fillets and nuggets.
If you have not had a flooding event or a stream that someone connects to your pond where the bullheads could have come from, you most certainly got contaminated stock. I have seen bullheads be mixed with both CC and FHM.
