There's a lot of sunnies and perch in that lake but I have pulled out some good sized smallmouth and walleyes. The typical walleye range from 15 to 25 inches.
Here is a snip form the DNR...
Sampled walleye had an average length and weight of 18.1 inches and 2.4 pounds, with fish measured up to 30.4 inches. While Potato Lake has excellent water quality and walleye spawning substrate, contribution from natural reproduction has been very sporadic in recent years. Recent surveys have shown that walleye fingerling stocking is contributing heavily to the walleye population in Potato Lake. The DNR has identified Potato Lake as a "Core" walleye lake that would benefit from increased walleye stocking. Potato Lake is a good candidate for increased walleye stocking due to its popularity as a walleye fishery and for having a good forage base of yellow perch and tullibee (cisco) that helps in the survival of stocked walleye fingerlings. Starting in the fall of 2005 the walleye fingerling stocking rate on Potato was increased.
Northern pike were sampled in moderate numbers (6.4 pike/gillnet), within the range "typical" for this lake class. Northern pike abundance in past surveys has fluctuated from low to moderate numbers. Sampled northern pike had an average length and weight of 22.1 inches and 2.7 pounds. The proportion of larger pike (> 28.0 inches) sampled, was low when compared to other area lakes.
Potato Lake supports both a smallmouth bass and largemouth bass fishery. Smallmouth bass are abundant in the rock and gravel bars of the main basin, while largemouth are less abundant, but are found in the bulrush stands and submerged aquatic vegetation beds of the west and east arms. Anglers have reported that the smallmouth bass population has been increasing since the late 1980's.
If you've got short, stubby fingers and wear reading glasses, any relaxation you would normally derive from fly fishing is completely eliminated when you try to tie on a fly. ~ Jack Ohman, Fear of Fly Fishing, 1988