Furacilin should be used to treat the rotten tail and body of fish. Furacilin, also known as yellow powder, is a common drug, which can be used in many times and belongs to the universal fish medicine. Its main function is sterilization. It should be noted that the dosage of this drug is also particular. If it is excessive, the water body will turn yellow, and at the same time, it may cause biting and damage the ecological environment in the fish tank, which is also very unfavorable for subsequent feeding.

1. Water quality deterioration: Usually, fish have rotten tails and bodies because of the deterioration of water quality. The water for fish farming should be changed regularly, otherwise the number of harmful bacteria in the water will increase, and ammonia nitrogen and other substances will accumulate slowly, which is harmful to the health of fish. When changing water, pay attention to the same temperature of old water and new water, so that fish can adapt.

2. Bacterial infection: Bacterial infection can also lead to rotten tail and rotten body of fish. This situation is usually due to the fact that the equipment and food put into the tank are not disinfected, and the environment in the tank is not good, resulting in a large number of bacteria breeding. If you want to avoid bacterial infection, you should do a good job of disinfection, especially live bait, which must be disinfected and fed.

3. New water stimulation: If you change too much water for a fish, the new water will also stimulate the fish, which will lead to its rotten tail and body. Usually, the water should not be changed too frequently, and it can be changed every five to seven days. The amount of water should not exceed one third of the total amount each time, and it is usually enough to change one quarter or one fifth.