If it is serious, it is best to isolate or give up, so as not to affect other fish.
First of all, you can go to the flower, bird, insect and fish market to buy medicine. There is a special white spot disease for fish, which is the most convenient and crucial.
Secondly, we should do a good job in the filtration system of water circulation and check the water quality. The water change time can be considered shorter.
There is also feeding. Pay attention to the shelf life when buying feed, and whether it is the special feed for this fish. Feed will also produce some bacteria in water.