Get yerself a kan of dogfood and punch holes in it and through it in there the night before and come back the next morning and fish around the can. We always used chicken liver for bait but its kinda hard to stay on the hook so use a ladys stocking and put the liver in that and hook through the stocking as it will stay on longer. Catfish are usually nocturnal so the best fishing is at night or early morning and evening.
The only way your going to know if there big catfish there is to fish it.
Good luck.

Bobby