Prevention Methods for Tailocyst Disease in Mandarin Fish Aquaculture

Mandarin fish tailocyst disease was widespread in our province last year, causing significant economic losses to farmers. Mandarin fish tailocyst worms parasitize the gills of fish. The cysts are round or tumor-shaped, white, formed by the aggregation of multiple small oval capsules. The sites where the cysts parasitize cause localized congestion or ulceration of the gill tissue, and sometimes the entire outer gill filament is covered with cysts, preventing the operculum from closing completely. Diseased fish become emaciated and darkened, and then die in large numbers. Currently, there is no specific drug treatment for Mandarin fish tailocyst disease, so only the following methods can be adopted for prevention.

1. Rotate the stocking of different fish species in ponds. Before stocking Mandarin fish, thoroughly clear the pond using a mixture of bleaching powder and lime.

2. Before purchasing Mandarin fish fry, find out about the disease situation at the supplying fish farm. Do not purchase Mandarin fish fry from a farm where the disease has occurred.

3. Use 10 g of bleaching powder and 8 g of copper sulfate per cubic meter of water. Dissolve them separately, mix them, and add to the water. When the water temperature is 10-20°C, soak the fingerlings for 20-30 minutes for disinfection.

4. Mandarin fish ponds should have an appropriate amount of aquatic plants to keep the water clean. From April to September, regularly splash the entire pond with a 5:2 mixture of copper sulfate and ferrous sulfate at a concentration of 0.7×10-6 once a month. In summer, apply the treatment on sunny afternoons, and the next day promptly change and add an appropriate amount of water.