Saprolegnia. The pathogens are saprolegnia and mussels. The hyphae are slender and branched. One end of them is root-like and is born in the skin of the lionfish, while the rest are exposed outside the body. The hyphae are up to 3 cm long, gray-white and soft like cotton wool. In the early stage of the disease, the mucus on the body surface of the diseased fish increases, forming a layer of white nebula. In the later stage of the disease, the mycelium penetrates deep into the skin, and the mortality rate is high.

You can choose 0.03 grams of malachite green or methylene blue, dissolved in 10 Kilograms of water, the diseased fish soaked for 3-5 minutes, and then rinsed with water, put into the aquarium. It takes multiple doses to heal.