I've had a few small ones. All on a quick stop rig with luncheon meat. From what I'm lead to believe is that they don't feed on the bottom, so you want a buoyant, slow sinking bait. They naturally feed on vegetation, so get near the weeds or lilies, etc.
A good Angler I know caught a 33lb er with tiger loaf, floating on its nose, he clotheslines across to a branch to keep the line out of the water. He's had quite a few with that method, but only in warmer weather.
Good luck with your quest and I hope to see you've nailed one in the catch report