A few years back, we wired the lids on ten black plastic garbage cans and cut six inch holes in the tops. We then staked the containers out in the pond, hoping that the bullheads would spawn in the containers. They did. The cans barely floated but it was enough to allow us to locate each can. Every other day we carefully turned the hole up and allowed the water to slowly flow out of the container. We did a lot of dry-run pre spawn, spawn, and post spawn container lifting were able to remove adults and eggs. After doing that for three years, we no longer had a bullhead problem.
