In English, you can describe "suan cai yu" as "pickled mustard greens fish." This dish is a popular Chinese recipe that consists of fish cooked with pickled mustard greens, a type of fermented vegetables. It is typically made with freshwater fish, such as carp or catfish, and seasoned with ginger, garlic, and chili peppers. The pickled mustard greens add a sour and spicy flavor to the dish, making it a unique and flavorful meal. Some variations of the recipe may also include other ingredients, such as tofu or eggplant, to add texture and flavor to the dish.