Common Winter Disease Prevention and Treatment Methods for Freshwater Piranha

In winter, when the water temperature is between 15°C—20°C, juvenile freshwater piranha are prone to Ichthyophthirius disease, white skin disease, and Dactylogyrus disease. During overwintering, freshwater piranha are prone to saprolegniasis, water mold disease, and Trichodina disease.

The symptoms and prevention and treatment methods for these diseases are introduced below:

1. Ichthyophthirius disease. A large amount of mucus appears on the body surface of diseased fish; in severe infections, they appear cloud-white in the water. Prevention and treatment: Before the fingerlings enter the pond, microscopically examine the body surface and gills of the fish. If Ichthyophthirius is found, apply 0.1 g of mercurous nitrate per cubic meter of water mixed with water and splash it over the entire pond, once a day for 3 consecutive days.

2. White skin disease. At the initial onset, the body surface, dorsal fin, caudal fin, and jaw of the diseased fish turn slightly white, and the scales at the whitened areas fall off at a touch. In severe cases, the fish loses balance, spins in the water, swims slowly, or hangs at the water surface with the head up and tail down. The time from onset to death is short; within 3 days the mortality rate can reach over 60%. Prevention and treatment: Do not injure the fish during the rearing process. At onset, apply 1 g of bleaching powder per cubic meter of water mixed with water and splash it over the entire pond. Once a day for 3 consecutive days. Or soak the diseased fish in 12.5 g of chlortetracycline or 25 g of oxytetracycline per cubic meter of water for 30 minutes.

3. Saprolegniasis. The skin of the diseased fish becomes inflamed; in severe cases the scales fall off, the muscles rot, forming round lesions, the fish loses balance, swims slowly, and soon dies. Prevention and treatment: Avoid injuring the fish during introduction into the pond and transfer between ponds. At onset, apply 1 g of bleaching powder per cubic meter of water mixed with water and splash it over the entire pond, once a day for 3 consecutive times.

4. Water mold disease. The body surface of the diseased fish has clustered hyphae, movements are sluggish, tissues necrose, and the fish soon loses balance and dies. Prevention and treatment: Control the overwintering pond water temperature at 24°C—27°C and prevent injury to the fish. At onset, soak in 20 g of potassium permanganate per cubic meter of water for 20—30 minutes, or apply 0.5 g of copper sulfate and 0.2 g of ferrous sulfate per cubic meter of water mixed with water and splash over the entire pond, once a day for 3 consecutive times.

5. Trichodina disease. The disease occurs only after the fish body is parasitized by large numbers of rotifers. Prevention and treatment: Apply 0.5 g of copper sulfate and 0.2 g of ferrous sulfate per cubic meter of water mixed with water and splash over the entire pond, once a day for 3 consecutive days.