How to Prevent and Treat Saprolegnia (Water Mold) in Fish? A Detailed Guide to Practical Methods
How to Prevent and Treat Saprolegnia in Fish
Saprolegnia is the most common disease in aquaculture. The treatment drug widely used at present is malachite green, but because malachite green is carcinogenic and teratogenic, the state has placed it on the list of banned fishery drugs. So what measures should we take now to prevent and treat saprolegnia?
1. Before stocking fish, use quicklime to clear and disinfect the pond. For every 667 sq m of pond, use 100 kg of quicklime, slake it in water and sprinkle it evenly over the whole pond; this can noticeably reduce the probability of this disease occurring.
2. Avoid injuring the fish. During catching, transport and stocking, handle the fish quickly and gently, and try to avoid injuring them. In addition, stock fish as far as possible to avoid low-temperature weather.
3. Soak and disinfect the fish. Before stocking the fish in the pond, soak them in 3%-5% salt water for 5-10 minutes.
4. Sprinkle over the whole pond. When the fish in the pond have saprolegnia, we can use the following methods to treat them.
(1) When the water depth is 1 m, for every 667 sq m of water surface, use 2.5 kg of water pepper (Polygonum hydropiper), 0.5 kg of cayratia (Cayratia japonica) and 2 kg of Chinese wingnut leaves (Pterocarya stenoptera), boil them together to make a decoction, dilute the decoction with water and splash it over the whole pond once a day for 2-3 consecutive times.
(2) When the water depth is 1 m, for every 667 sq m of water surface, use 5 kg of sweet flag (Acorus calamus) juice and 1 kg of salt, add them to 20 kg of human urine and mix evenly, then slake in water and splash over the whole pond.
(3) Slake methylene blue in water and sprinkle it evenly over the whole pond so that the methylene blue concentration in the pond water reaches 2-3 ppm, then sprinkle it once more after 3-4 days.
5. Points to note during artificial breeding.
(1) Try not to choose injured fish as brood fish. If injured brood fish are put into the pond, sulfonamide ointment must be applied to the affected areas of the injured brood fish.
(2) Prevention and treatment of saprolegnia in fish eggs. First, try to increase the fertilization rate of the fish eggs. Second, soak the spawning nests in 3%-5% formalin solution for 2-3 minutes or in 1%-3% salt water solution for 20 minutes. Third, splash methylene blue aqueous solution into the water body used for flowing-water incubation so that the methylene blue concentration in the water body reaches 5 ppm.
1. Before stocking fish, use quicklime to clear and disinfect the pond. For every 667 sq m of pond, use 100 kg of quicklime, slake it in water and sprinkle it evenly over the whole pond; this can noticeably reduce the probability of this disease occurring.
2. Avoid injuring the fish. During catching, transport and stocking, handle the fish quickly and gently, and try to avoid injuring them. In addition, stock fish as far as possible to avoid low-temperature weather.
3. Soak and disinfect the fish. Before stocking the fish in the pond, soak them in 3%-5% salt water for 5-10 minutes.
4. Sprinkle over the whole pond. When the fish in the pond have saprolegnia, we can use the following methods to treat them.
(1) When the water depth is 1 m, for every 667 sq m of water surface, use 2.5 kg of water pepper (Polygonum hydropiper), 0.5 kg of cayratia (Cayratia japonica) and 2 kg of Chinese wingnut leaves (Pterocarya stenoptera), boil them together to make a decoction, dilute the decoction with water and splash it over the whole pond once a day for 2-3 consecutive times.
(2) When the water depth is 1 m, for every 667 sq m of water surface, use 5 kg of sweet flag (Acorus calamus) juice and 1 kg of salt, add them to 20 kg of human urine and mix evenly, then slake in water and splash over the whole pond.
(3) Slake methylene blue in water and sprinkle it evenly over the whole pond so that the methylene blue concentration in the pond water reaches 2-3 ppm, then sprinkle it once more after 3-4 days.
5. Points to note during artificial breeding.
(1) Try not to choose injured fish as brood fish. If injured brood fish are put into the pond, sulfonamide ointment must be applied to the affected areas of the injured brood fish.
(2) Prevention and treatment of saprolegnia in fish eggs. First, try to increase the fertilization rate of the fish eggs. Second, soak the spawning nests in 3%-5% formalin solution for 2-3 minutes or in 1%-3% salt water solution for 20 minutes. Third, splash methylene blue aqueous solution into the water body used for flowing-water incubation so that the methylene blue concentration in the water body reaches 5 ppm.