Brush fish with canola oil. Season fish with salt and ground black pepper. Place fillets in a greased grill basket. For a charcoal grill, place grill basket on grill rack directly over medium coals for 6 to 9 minutes or until fish flakes easily when tested with a fork. (For a gas grill, preheat grill. Reduce heat to medium. Place grill basket on grill rack over heat. Cover and grill as above.)
Meanwhile for the sauce, cook the butter and tomato over medium heat till butter has just melted. Stir in the water, lemon juice and white pepper; remove heat. Set aside.
Just before serving, stir basil into sauce. Top each fillet with a spoonful of sauce. Makes 6 to 8 servings.