In a bowl combine the cornmeal, flour, salt, cayenne pepper, and garlic powder. Pour mixture onto a pie plate. Coat the catfish fillets with mixture, shaking off excess.
Fill a 12 inch skillet half full with vegetable oil and heat it to 350 degrees. Add fillets to oil and fry until golden brown, about 56 minutes.
Put the fillets on serving plates, add a spoonful of tartar sauce, and serve.