1. Reason: The rotten scales of fish may be due to rot, and the main cause of this disease is poor water quality. After the fish suffers from rot, the body will be congested locally, and the scales will fall off and fester.

2. Treatment: Breeders need to change water immediately to keep the water clean. Crude salt should also be added to the water to reduce the chance of infection. If conditions permit, it is best to turn on the circulating filtration system and oxygen pump.

1. Reason: Fish scale ulceration may also be caused by standing scale disease, which is easy to occur when the water temperature is low or the temperature difference is too large. The scales of fish suffering from this disease will explode first, and then the roots of the scales will fester.

2. Treatment: The breeder needs to fish out the sick fish immediately and put it in a separate container. And use furacilin powder medicated bath, and the concentration should be controlled at 1.5-2ppm. If the fish has swelled, it needs to be treated with antibiotics.

1. Reason: The fish scales are rotten, and it is possible that they suffer from gill rot. Although the main affected part of gill rot disease is gill, it can also cause fish scales around gill to fall off and fester.

2. Treatment: Breeders need to use potassium permanganate solution for medicated bath once a day, and the time of each medicated bath can be controlled for about 15 minutes.