Combine first 4 ingredients and 2 teaspoons salt in a large shallow dish. Sprinkle catfish fillets evenly with remaining 1/2 teaspoon salt, and dredge in cornmeal mixture, coating evenly.
Pour vegetable oil to a depth of 2 inches into a Dutch oven; heat to 350°. Fry fillets, in batches, 5 to 6 minutes or until golden; drain on paper towels.
Note: For a quick weeknight version, skip the deep fryer. Cook catfish in 2 tablespoons hot oil, per batch, in a nonstick skillet 5 minutes on each side.