How to prevent and treat dactylogyrosis in tilapia farming

[Cause]Dactylogyrus worms use their anchor hooks and marginal hooklets to hook onto the gill filaments and move constantly, causing damage to the gill tissue. This disease mainly harms fry and fingerlings, and heavy infestation can cause mass mortality of fry and fingerlings. The parasite's suitable water temperature is 20-25°C, and the disease occurs in summer, autumn and the overwintering period.

[Symptoms]The gills of diseased fish are mostly covered with mucus, the gill filaments are swollen, breathing is difficult, the body color turns black, the fish stop feeding, become thin and weak, swim feebly and float at the water surface; diseased fish are restless, jump, and swim slowly. This disease often occurs together with trichodiniasis, and in severe cases can cause mass mortality of fish. When the parasite infests the body surface, mucus secretion increases, and congestion and hemorrhagic spots appear.[Prevention and treatment]Prevention: ① Parasitic diseases should focus on prevention; please refer to "② Prevention of parasitic diseases". ② When stocking fry and fingerlings, soak them in potassium permanganate (15 g per 1 cubic meter of water) or Bai'anwei (1 mL per 1 cubic meter of water) for 15-20 minutes. Treatment: ① Soak diseased fish in Bai'anwei or Chongcijing (1.2 mL per 1 cubic meter of water) for 10 minutes. ② Splash Bai'anwei over the whole pond (1 bottle per 2 mu); on the morning of the next day, use Jiedu Chaoshuang (1 bottle per 3 mu) to detoxify, and 3 hours later, mix 1 packet of Liukongdi Jiankang + 1 packet of Disu'an and broadcast dry over the whole pond at 3 mu per dose. ③ Mix Huoxing Suanbao, Bencao Dakang, Baogan Cuzhangling and Qingyuan each at 1% into the feed and feed twice a day for 3 consecutive days.