Saprolegnia. Ringtail hangers are restless and often rub the affected area on fish tanks, aquatic plants, etc. to relieve pain. Fish mucus increases, the muscles in the affected area rot, lack of energy, and loss of appetite. In common water, there are clusters of flocculent hyphae that fall off the fish body, which eventually leads to the death of the fish body.

Dissolve 0.7 grams of methylene blue in 100 kilograms of water, Make an aqueous solution, put the diseased fish into it, bathe for 15-20 minutes, and see that the mycelium falls off.