Rinse catfish and pat dry with paper towels. Sprinkle both sides of catfish with pepper. Lightly spray a grill basket or grill rack with vegetable oil spray. Place fish in basket or on rack.
Grill catfish on uncovered grill directly over medium-hot coals about 5 minutes per side, or until fish flakes easily when tested with a fork.
Meanwhile, for sauce, spray a small saucepan with vegetable oil spray. Cook garlic over medium heat for 2 minutes, stirring occasionally. Stir in flour. Add milk all at once, stirring well. Add mustard and lemon peel. Cook and stir until thickened and bubbly, about 3 to 5 minutes. Stir in chopped fresh herbs. Cook and stir 1 minute.
Serve grilled catfish with sauce. Garnish with fresh herbs.
Calories: 195 Protein: 31 g Carbohydrates: 12 g Total Fat: 2 g Saturated Fat: 0 g Polyunsaturated Fat: 1 g Monounsaturated Fat: 0 g Cholesterol: 72 mg Sodium: 249 mg