UNLESS caught with a hook and pole. then you can use whatever size you want, but the bait still counts toward your daily creel limit. the 5 inch rule is if you catch them (or any other fish other than shad and asian carp and asian carp cannot be used or kept alive) in a bait trap, sein or cast net, or any method other than a pole and line. I don't mean to sound cocky or arrogant but I have read the code book over and over when it comes to catfish bait, and I fish by the code book. that said, maybe I'm wrong! after all, I am only human. but I'm from the show-me state so show me!