There are some inexpensive trapping methods also.
Take a plastic garbage can with a lid. Cut a hole the size of a soda can in the lid. Then secure the lid to the garbage can with some wire.
Put some kind of bait like fish food, bread, or roadkill in the can and sink it in the pond. Have a rope tied to the garbage can and the shore. Let the can sit for a few hours, then quickly haul it in and see what you get.
You may have to experiment with the best places to sink the can.
It does work, but you have to keep at it.
This in conjunction with getting some bigger bass in there will start to reduce the bullhead numbers, along with removal by fishing of course.
While it's not very recommended to stock your pond with fish from other waters, you can catch bass elswhere and put them in your pond; this would be the most cost effective way of getting more bass.
