Rinse fish in cold water; pat dry. Place in a large mixing bowl; pour salad dressing over fish. Cover and refrigerate 4 hours or overnight.
Place trout on grill, skin-side down, 4 to 5 inches from hot coals. Grill without turning 10 minutes or until fish flakes easily when tested with a fork.
Transfer fish to a warm serving platter. Garnish with lemon wedges. Serve immediately.