Move oven rack to position slightly above middle of oven. Heat oven to 500 degrees. Remove and discard skin from fish. Cut fish into 2x 1 1/2" pieces.
Mix buttermilk and egg white with fork. MIx cornmeal, bread crumbs, and cajun creole seasoning. Dip fish into buttermilk mixture, then coat with cornmeal mixture. Place in ungreased rectangular pan, 13x9x2". Lightly spray cooking spray on fish.
Bake uncovered about 10 minutes or until fish flakes easily with fork. Serve with lemon wedges.