It is normal to catch catfish when you shoot docks. I usually catch at least 3 or 4. When you are shooting docks you can catch almost any fish that is in the lake. All fish love the structure and shade of docks. One of the fun things about dock shooting is every dock is a new adventure. I have caught 88 fish off of one dock and they were still biting but we had a limit. Dock fishing is fun and it kind of reminds me of bass fishing. Good luck with your dock shooting.