You can usually buy a good one for catching bait at your local tackle shops. The descriptions on here are good. They look like two inverted funnels small sides facing each other > < with wire all around. They usually separate in the middle which is where you tie your bait and empty your catch. If you have ever seen Craws up close and personal you know that they can swim quickly and get where they want to go. They can swim up, around, in, etc. They can get out of traps but it is more difficult. You won't have any problem getting them into the trap as long as you use a chicken bone with a little meat on it.