Cotton Lake has a diverse fish community that includes Bluegill, Black Crappie, Largemouth Bass, Northern Pike, Yellow Perch, and Walleye. Cotton Lake also contains Cisco, a coldwater species that requires cool, well oxygenated refuge areas during the heat of summer. Walleye fingerlings are stocked into Cotton Lake every other year and abundant year-classes of Walleye corresponded to years when stocking occurred. At 3.8 fish per net in 2016, gill net catch for Walleye was below average for Cotton Lake but above what is expected for similar lakes. Sampled Walleyes ranged from 9.4 to 24.5 inches with an average length of 15.7 inches. A special regulation for Northern Pike was implemented on Cotton Lake in 2003. The regulation required the release of pike between 24 and 36 inches in length. After eight years the pike population did not show signs of improved size structure so the regulation was discontinued in 2011. Northern Pike gill net catch was 9.8 fish per net in 2016, which is near the historical average for Cotton Lake but above what is expected for similar lakes. Sampled Northern Pike ranged from 9.8 to 23.4 inches with a mean of 15.7 inches. As is the case with some other area lakes, Northern Pike numbers have increased in recent years while size and growth have decreased. Anglers are encouraged to keep smaller Northern Pike and release larger ones to help improve size structure. Bluegill catch has remained well above both the historical average for the lake and what is expected for similar lakes. Bluegill trap net catch was 49.7 fish per net in 2016, and sampled fish ranged from 4.0 to 8.9 inches with a mean of 7.3 inches. On average, it was found that it takes Bluegill nine years to reach 8 inches. Trap net catch rate was 3.7 Black Crappies and 1.3 Largemouth Bass per set, both just above the historical averages for each species. Black Crappies ranged in length from 8.4 to 11.6 inches and averaged 9.6 inches. Black Crappie were found to reach 10 inches in about 6-7 years. Largemouth Bass ranged from 6.8 to 18.3 inches and averaged 14.4 inches. Yellow Perch catch was 13.3 fish per net. This catch is below the historical average of 23.6 fish per net but within what is expected for similar lakes. Mean Yellow Perch length was 8.4 inches, and lengths ranged from 5.2 to 11.1 inches. In 2016, four Cisco were caught in gill nets, and they ranged in size from 16.7 to 18.7 inches.