Combine the first 3 ingredients in a shallow dish. Dredge catfish fillets in the cornmeal mixture.
Melt the butter in a large nonstick skillet coated with cooking spray over medium-high heat. Add catfish fillets, and cook for 5 minutes on each side or until fish flakes easily when tested with a fork. Remove catfish fillets from heat, and keep warm.
Combine the coleslaw and dressing. Cut hoagie rolls in half horizontally, and spoon 1/2 cup slaw over bottom halves of rolls. Top each with 1 fillet and tops of rolls.
