Combine flour, cornmeal, garlic powder and salt in a large bowl.
Dredge catfish in the flour mixture, shaking off excess.
Fill a large heavy-bottomed pot or 12-inch skillet with vegetable oil until it comes halfway up the side. Heat to 350°F.
Once hot, carefully add the catfish, being careful not to overcrowd. Cook in two batches if necessary. Fry until golden brown, turning halfway, 5 to 6 minutes. Remove and drain on paper towels. Serve hot.
