Whisk lemon juice, olive oil, crushed garlic cloves and grated lemon peel in small bowl to blend. Stir in capers and basil. Season vinaigrette with salt and pepper to taste. Let stand at room temperature.
Prepare your fire on your barbecue, (high heat) or use broiler. Season fillets with salt and pepper and coat fillets with vinaigrette. Cook until fish flakes, be careful not to break fillet when turning. When fish is done place fillet on platter and pour remaining vinaigrette over fish.