Sweet and Sour Fish

Marinate. In a bowl, add fish and mix in the wine and salt. Add the egg and flour then mix until the fish slices are fully coated. Add the oil. Set aside.
Preheat the oil. Heat at least 1 cup of oil in a wok over high heat. Dip a chopstick into the oil. If the oil starts steadily bubbling, then the oil is hot enough for frying.
Fry the Fish. Working in batches, use chopsticks to drop the fish slices into the wok one by one. Deep-fry the fish slices until lightly golden. Do not overcook the fish. Transfer them to a paper towel-lined plate or wire cooling tray.
In a bowl, combine all sweet and sour ingredients. Set aside.
In a wok, heat 1 teaspoon of oil over high heat. Cook garlic and ginger until fragrant for 10 seconds.
Whisk in the sweet and sour sauce into the wok and simmer, stirring occasionally until the sauce is thickened and glossy for 5 minutes (about 1¼ cup of sauce, just enough sauce to wrap around the crispy pieces of fish).
Taste and adjust the seasoning with extra sugar and/or vinegar if needed. Remove from the heat, and set aside.
In a clean wok, heat 1½ tablespoons of oil over high heat. Cook the onion, red bell pepper, and green bell pepper until tender.
Add the fish back into the skillet. Pour in the sauce and toss to combine. Remove from the heat and serve.
Or for a crispier result, you can pour the sweet and sour sauce with vegetable mixture over the fish before serving.