Lake Mendota has some monsters but they are hard to find at times and finicky when you do. I’ve had schools of dinner platers on my camera before in the hundreds.
Green, Geneva, & Mendota all have monster gills. Takes a lot of searching to find them. Open water fishing on these lakes I usually find them suspended – much like searching open basin crappies. Winter time, if your getting average to smaller gills, go deeper and start on the deepest weed lines. Sure would like to go back to pre-1994 on Mendota!