Heat the oil in a wok over a high heat until the oil starts to shimmer. Add the garlic and stir-fry for a few seconds, then tip in the scallops and stir-fry for 1 minute until golden.
Add the crab sticks, prawns, fish, oyster and soy sauces, sugar and peppercorns, in that order, giving the dish a quick stir between each addition.
Cook for 1 more minute, until all the fish is heated through and well coated in the sauce. Serve with rice, if liked.