Coldwater catfish hunt mainly be smell, so a nice, juicy, bloody, stinky bait will do you good. Although I've heard of cats being caught on lures, i haven't had any luck with them.
you could also try using a small piece of spunge attatched to a single or trebble hook. This will be rather boyant, so you'll need some weights, but after soaking the spunge in some smelly bait liquid (whatever's left over in the bottom of a jar of salmon eggs, or meat juices (fat or blood)). This works well, because, unlike bait fish, the spunge collapses as soon as the fish grabs it, allowing the hook to dig in on the very first strike.
best of luck.