The white spot disease of goldfish is related to nutrition and physique. The pathogen is "small melon bug with many children", which generally only occurs in aquariums or small mud ponds, and rarely occurs in mud ponds. The onset season is usually in warm winter or early spring, when the water temperature is 18-20℃. If the fish is infected, the disease can break out or exist for a long time above 20℃ in the environment where the water temperature is lower than 65438 05℃. Healthy goldfish are not prone to this disease. Clean the fish tank before releasing the fish, and spray it with 0.7 ppm mixture of copper sulfate and ferrous sulfate (5: 2) for disinfection. Keeping the water temperature at about 25℃ and hanging copper wire (2g per 100 liter of water) can prevent the occurrence of this disease. Feeding fresh fish and worms regularly can play a preventive role. Add a mixture of formalin and malachite green to the aquarium, and change 30% water the next day. After three days, medication was given again to strengthen nutrition and improve the fish's physique.