Koi with white frost indicates that it has water mold, so it is necessary to change water properly, raise water temperature at the same time, or soak it with povidone iodine. Water mold is one of the common diseases of ornamental fish. There are many kinds of diseases, such as water mold and cotton mold. Usually, after the fish is injured, the bacteria will invade from the wound and then grow hyphae from it, which looks like hoarfrost. Because this disease often suffers from low temperature, heating up has a very good preventive effect.

1. Raise water temperature: Water mold is most likely to occur when the water temperature is low, so raising water temperature can play a preventive role. You can use a heating rod to keep the water at a constant temperature, and the temperature is controlled at about 25 ℃. If it is some fish with strong heat resistance, you can even raise the temperature to 28-30 ℃.

2. Avoid injury: The cause of water mold is water mold, which has many kinds, but generally only after fish are injured will it invade the wound and cause it to get sick. Therefore, we must be careful when carrying, changing water and feeding at ordinary times, don't hurt it, and don't put too sharp Stone in the tank.

3. Light sterilization: Ultraviolet rays have sterilization effect, while fish are kept in water tanks, and the glass itself will pattern ultraviolet rays in sunlight, so it is necessary to install a special lamp in the tank, which can not only kill fungi in the tank, but also play a preventive role.