The reasons why goldfish lose scales:

1. High stocking density. There are too many fish in the breeding environment, the living environment is crowded, and the fish do not have enough space to move. They will bump into each other when swimming, and the fish scales will rub against each other, which will cause scales to fall off if they occur too often.

2. Injured in a fight. When a fish is fighting with other fish, the scales will fall off if the fish is injured.

3. The water quality is too poor. Goldfish losing scales may be caused by poor water quality. If the water they live in is too dirty, they may lose scales.

4. Pine scale disease. Goldfish losing scales may also be suffering from pine scale disease, which is mainly due to bacterial infection. When they suffer from pine scale disease, their body scales will slowly fall off.

Methods to deal with goldfish scale loss:

1. Reduce the breeding density. The number in each fish tank should not be too large. You can use several fish tanks to raise them. Or simply change to a larger fish tank so that there is no need to separate tanks.

2. Change the water. Change the water for them first to keep the water clean, but the amount of water change should not be too large, control it to one-third of the total water volume.

3. Isolation treatment. Isolating injured goldfish can prevent their wounds from becoming infected, and apply anti-inflammatory drugs to them to speed up their recovery.

4. Medicinal bath. Use nitrofurazone powder to give them a medicated bath, once a day for 20-30 minutes each time, and the scale loss will be restored in about 7 days.