Poor feeding the day after tomorrow. Besides congenital malformation, black fish heads are generally caused by poor breeding, which is also related to congenital genetic strains. Long-term feeding is not enough to starve to death, and diseases and visceral injuries will lead to thin fish. If it is a small fish, after a period of careful feeding, it can gradually return to normal. Big fish are difficult to adjust, because it is difficult to return to the original after years of accumulation. Black fish heads are big and thin because they are not well bred. Black snakehead is a common edible fish in China, with large size, fast growth and high economic value. Snakehead has less bone spurs, high meat content and rich nutrition, which is higher than protein contained in chicken and beef. As a medicine, snakehead has the functions of removing blood stasis, promoting tissue regeneration, nourishing and recuperating. The postoperative snakehead has the functions of promoting granulation, enriching blood and promoting wound healing, and its nutritional value is very rich.