Preheat the oven to 200 degrees C. Brush a large sheet of thick foil with the oil and place the fish on top. Place the lime slices inside the fish and scatter over the spring onions, carrot, ginger and garlic. Drizzle over the soy sauce and sesame oil, and sprinkle over the coriander leaves. Bring the ends of the foil together and fold and twist to seal in the fish. Place on a baking tray. Bake for 30–35 minutes or until the fish flakes easily (open the parcel to check).
Meanwhile, place the noodles in a saucepan of boiling water, return to the boil and simmer for 3 minutes. Or cook them according to the packet instructions. Drain well. Heat the oil in a wok, add the onions and garlic, and cook over a high heat for 30 seconds. Add the bean sprouts and cook for 1 minute or until they begin to soften. Add the noodles together with the soy sauce. Cook over high heat for 2–3 minutes, stirring and tossing well.
Remove the fish from the oven, unwrap and transfer to a hot serving platter. Garnish with coriander leaves and lime halves. Serve the fish cut into slices, with the noodles.