One of our go to baits is live bluegill. Channel catfish love what they know! Check your state. In some states, you cannot use bluegill as bait. We fish the bluegill whole and live. The normal hook placement is the upper back portion of the tail. Don't be afraid to fish a small to medium size blue gill. however big the catfish mouth is, that's the size bluegill the catfish will eat.
We catch our bluegill with a small hook on a bream pole and then toss them on a larger spinner into the lake. That's double the fun, and this especially good for kids. When things are slow, they are catching little fish and when the big fish gets on the line Oh Boy!