White spot disease. White spot disease is also known as small melon disease. After the multicolored hanging disease, small white spots grow on the operculum and fin rays first, and then cover the whole body. Later, the mucus on the body surface increases, and the white spots become white cysts. , seems to be covered with a white film. Multicolored hangings often have significantly reduced activities, floating on the water or gathering in a corner. If they are not treated in time, they will gradually lose weight and even die.

Use 2 parts per million (2ppm) hydrochloric acid at 28～30℃ Soak in quinine solution for 3 to 5 days; or soak in mercurous nitrate solution of 2 parts per million (2ppm) for 30 minutes.