1.Preheat oven to 200°C (180°C fan-forced).
2.Cut 3 deep slits in each side of fish; place fish in oiled baking dish.
3.Rub ginger into fish; drizzle with combined oil, wine, soy sauce and sugar. Bake fish, covered, about 25 minutes or until fish is cooked through.
4.Serve fish drizzled with some of the pan juices, topped with onion.