Thanks for the responses.
I trapped them with a minnow trap. It's basically a cylindrical plastic cage with an entrance on each end that cones in. You put a slice of bread in it and the minnows swim right in. The trouble is they are to stupid to figure out how to get back out, which I'm guessing, is why they are near the bottom of the food chain.
The pond I trapped them is has no preditors so it's teaming with fatheads.
One more question. My pond is so small that I'm not really keen on using an sort of artificial structure. Is there any way I can facilitate maximum fathead breeding structure without comprimising natural habitat?