The Castle Rock Flowage has earned a reputation as an excellent fishery. The wide variety of fish species found in the flowage offers anglers year'round action, in a vast number of areas. The Castle Rock Flowage, like some other waters, contains some fish species on the State Health Advisory List that may have higher than acceptable levels of mercury or PCBs. For current information please check with the park office. The best places to catch fish from Buckhorn's shores are off the accessible fishing pier by the North Picnic Area, and from the shoreline by the canoe launch.
Walleyes are the most sought after species in the flowage.
They are hard to beat as table fare, and reach trophy size all along the Wisconsin River system. Fishing for walleyes can be especially good in spring and fall, and during morning and evening hours. Drop-offs along the old river channels are good spots to try. Use a jig and minnow or troll with a plug that imitates a small baitfish. The most popular areas are near the Buckhorn Bridge, the mouth of the Little Yellow River, and the railroad bridge on the northeast end of the flowage.