Place 1 cup low-fat buttermilk in a large zip-top plastic freezer bag; add 4 (6-ounce) catfish fillets, turning to coat. Seal and chill 20 minutes, turning once.
Remove catfish fillets from buttermilk, discarding buttermilk. Sprinkle catfish fillets evenly with 2 1/2 teaspoons salt-free Creole seasoning and 1/2 teaspoon salt.
Place 3 cups crushed cornflakes in a shallow dish. Dredge catfish fillets in cornflakes, pressing cornflakes gently onto each fillet. Place fillets on a rack coated with cooking spray in a roasting pan.
Bake catfish fillets at 425° for 30 to 35 minutes or until fish flakes with a fork. Serve catfish fillets immediately with lemon wedges.
Note: For testing purposes only, we used The Spice Hunter Cajun Creole Seasoning Salt Free.