Not sure if this is an option, but my grandfather put a couple flathead catfish in his pond. He did this for two reasons. 1) To help control populations, especially bullheads and 2) To provide huge fish for his two grandsons to "help him catch" down the road. The pond was about 2.5 acres. The first one was 48 lbs and the second one was 72 lbs when it was removed. I'm not sure exactly when they were put in, but they were removed in 1987 and 1989.
Huge fish for a pond that size, but ya know what? That was probably the healthiest our pond ever was. We caught lots of very nice bass, a number of them went to the taxidermist, and we had overall healthy populations of fish.
I'm going to put 1-2 in once I get the pond repaired and back to the way it should be.
