Fish body decay usually use bactericidal drugs, such as yellow powder, malachite green, oxytetracycline, penicillin and povidone iodine, etc. The cause of its body decay is generally disease, such as rotten fin disease, rotten tail disease, saprolegniasis and so on, in addition to drug treatment, but also to change water in time, properly raise the water temperature, and pay attention to salt. Do not feed during the illness, so as not to cause deterioration of the disease.