Furacilin should be used for rotten body and unfinished tail of ornamental fish. Furacilin is yellow powder, and it is also a common fish medicine, which can kill many bacteria, so it can treat many diseases. There are two ways to use it. One is to put it directly into the fish tank, change the water the next day, and then decide whether to add medicine according to the illness. The other is to prepare a treatment tank separately and give the fish a medicated bath, which is not easy to affect other healthy fish.

1. Water quality deteriorates: The reason why fish rot and tail is usually related to water quality. The water used for fish farming should be changed regularly. If the water is not changed for a long time, the water body will deteriorate. Usually, the water should be changed every five to seven days, and about a quarter of the water should be changed every time, while paying attention to keeping the temperature.

2. Sudden temperature change: If the temperature changes suddenly, the fish can't adapt, and the body will be rotten and the tail will be rotten. In the daily feeding process, the water temperature must be kept constant, the temperature difference between day and night should not be too large, and the temperature change during the day should be controlled at about 2 ℃, so that fish are not easily stimulated.

3. Infected bacteria: When a fish is infected with bacteria, it will also cause it to rot. Usually, in order to avoid bacteria entering the tank, anything entering the tank should be disinfected, whether it is utensils, landscaping or live bait, so as to ensure the safety of the fish tank.