Saprolegnia. The red top koi is restless, the fish body mucus increases, the muscles in the affected area rot, the spirit is sluggish, and the appetite is lost. 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.

The main reason in the breeding process of Danding koi is Caused by poor water quality, the disease usually occurs in winter and early spring.

It can be heated to 28-32℃ + 20% water change every day + 5/1000 of the lower salt. Note: Warming up and adding salt can't kill germs, but they can inhibit it. After the danding koi calmed down, they would recover naturally. For severe symptoms and deep wound festering, yellow powder or potassium permanganate or gentamicin can be applied directly + 5/1000 salt + insecticide.