If you want to catch the big catfish on the Potomac you're going to want to use cut Shad or cut herring not any of the bait you can buy in the stores. You're also going to need a boat to do it because you're going to have to net up the shad so you can use it for bait. This time of year you can get all the shad you want at the blue Plains discharge. I guarantee you most of the professional guides that fish all winter long on the Potomac net up hearing and Gizzard/ Hickory shad during the Spring runs and freeze it until they're ready to do serious fishing in the winter time where they catch the big ones.