Soak the fillets in cold water for 48 hours and then dry on a paper towel. Cut the fillet into slices.
Heat vegetable oil in a wok or other large skillet, add fish pieces, fry until golden brown. Transfer the fish to a paper towel, let it cool slightly, then break it into pieces.
Rinse bean sprouts well and sort, remove spoiled ones. Cut the green onions into 5 cm pieces.
Drain the oil from the pan, leaving only 2 tablespoons. Warm-up again. Put garlic in a frying pan, fry until slightly golden brown. Add bean sprouts and fish, cook for a couple of minutes.
Put the green onions in the pan, cook the hot fish salad for about 1 minute, pour over the soy sauce, cook the hot fish salad for about 1 minute more.