WHITE SPOT (ICH)
Ich, also known as white spot disease, is caused by the parasite, Ichthyophthirius multifiliis. Ich is usually visible as a small, white spot on your fish's skin. The ich parasite penetrates the skin or gills, burrows under the surface, and eats at the fish's flesh. Ich has a high mortality rate and is very infectious. If your tank contains multiple fish, all of your fish are likely infected. Once your fish is infected, it will develop the white, raised blister spots at the site of the parasite's penetration, and the parasite will rapidly multiply.
Use anti white spot medicines according to the tank size (Dosage 10 ml per 100 liters)
Monitoring and maintaining proper water temperature is critical to ensure the parasite is completely eliminated from your system. Many online forums recommend manipulating your tank temperature to speed up or immobilize ich, but it's essential to be extremely careful in doing this to avoid inflicting stress on your fish, weakening its immune system.