In addition to congenital malformation, large head and small body 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 fish wasting and shrivelling. If it is a small fish, after a period of careful feeding, it can gradually return to normal, and the big fish is difficult to recuperate because it is difficult to return for many years.