The structure created from the river beds makes Castle Rock Lake a productive and consistent fishing lake. Species such as walleye, white bass, and crappie are the most abundant, but many other species like northern pike, large mouth bass, small mouth bass, bluegills, redbreast sunfish, and perch are caught as well. Muskellunge (Musky), sturgeon, and catfish are also known to be present but in smaller numbers than other noted species. The lake is also known for being a winter refuge for bald eagle and a location the Wisconsin DNR is attempting to bring back wild osprey and wood duck populations too. In addition to the DNR's efforts the Federal Energy Regulatory Commission (FERC), UW-SP, and WRPCO have designated the area a wildlife refuge and completed an management plan for the refuge.
