First, thaw it with cold water (change the water several times), then peel it clean, and finally feed it with broth (preferably steamed) for two hours. At this time, the mussels can be cooked as seafood raw materials. If there is no stock, you can use onion, ginger, garlic, chicken essence, star anise, cinnamon and pepper to boil water instead of stock. This process is essential, otherwise it will be "... hard and fishy ..." as you said. As for the practice, you can cook and stir-fry, red (clear) burn, simmer soup, or add assorted hot pot.