White spot disease. Caused by the parasite Protozoa, a part or most of the blue pendant is covered with small white spots. Mainly affects the appetite of the fins and the blue hanging, and the blue hanging can often be seen rubbing the body. The whole body of the sick fish is covered with white spots, like being sprinkled with white powder.

Increase the temperature to 30 or even 34 degrees Celsius and add 3% concentration of small table salt . If it still does not work, it will be treated in a medicine tank alone.