Symptoms and Prevention of Protozoan Diseases in Lionfish

Pathogen: Saltwater Ichthyophthirius, the parasite body is spherical or oval, similar to Ichthyophthirius multifiliis, size 0.066-0.45×0.034-0.36mm, the entire body is covered with cilia, generally with four bead-like macronuclei.

Epidemiology: Saltwater Ichthyophthirius mainly parasitizes the gills, skin, fins and other parts of marine fish. It is prevalent in all coastal sea areas from mid-May to August each year. The suitable breeding temperature for Saltwater Ichthyophthirius is 20-25°C, and it is transmitted by *cysts and their larvae.

Symptoms: First, a large number of small white spots appear on the body surface. In severe cases, the fish body is covered with a layer of white film. Due to the destruction by the parasite, secondary bacterial infection can be caused, resulting in inflammation and necrosis of the fish epidermis, scales easily falling off, fin rays rotting and splitting. When parasitizing the gills, it destroys the gill filaments, and after bacterial infection, it causes gill rot. When the parasite invades the fish cornea, it causes inflammation and blindness. Sick fish have reduced appetite, become thin, and swim abnormally. The parasite can be identified by observation under a microscope.

Prevention and treatment methods: 1. Density should not be too high; 2. Soak sick fish in 0.4-1ppm malachite green for 5-10 minutes, and soak again the next day; 3. Soak in 60ppln formalin for 15-20 minutes, or for planted tanks, splash 20-30ppm over the entire tank; 4. Use insecticide powder mixed with freshwater to make 50ppm, and soak for 5 minutes.