Maybe try clipping the fins. Channel cats will definitely hit live baits, I've gotten some nice sized channel cats fishing live baits for flatheads.
Sometimes, I think they will just hit the bait in order to kill it (competition maybe?). Anyhow, I've taken some great channel cat hits on live baits that just buried the rod in the holder. A few of the stronger ones even made me think I had a small flathead at first!
Here's a channel cat I got at one of the forest preserves using a small bluegill below a slip float (also got a small northern that day).