predicts that the temperature in Guizhou in April will be between 8～24℃, and the water temperature will be between 7～22℃. The weather changes frequently, and low temperature and warm and humid climate alternate. Lightning and hail occur from time to time, water temperature changes greatly, and aquaculture diseases are beginning to increase. The prevention and control of the following diseases should be focused on.
1. Illness prediction
(1) Carp spring viremia:focus on carp species, especially carp fry under 1 year old. The disease is mainly prevalent in water temperature 13～20℃ In spring, the optimum temperature for an outbreak is 16-17℃, and the water temperature exceeds 22℃ generally without disease, and the mortality rate can reach 80%-90%.
(2) Gill rotten disease:It can occur from fingerlings to adult fish. It is popular from April to October. The suitable water temperature is 15～30℃, and the focus is on grass. , Carp, crucian carp, sturgeon and other cultured species.
(3) Saprolegniasis:Mainly harms various injured fish and eggs. The prevailing water temperature is 13～18℃. Fish body injury is an important cause of disease.
(4) Cucumber Insect Disease:Mainly harms the seedlings of various freshwater fish, the breeding temperature of Cucurbita vulgaris is 15～25℃, and it is mainly popular in spring In autumn, the disease is fast and the mortality rate is high.
2. Prevention measures
(1) Carp spring viremia:the disease is mainly prevention, and aquatic seed quarantine system must be implemented; fish breeding, water bodies, tools and facilities, etc. To do a good job of disinfection, water can be disinfected with iodine content of 100 mg/L iodophor or trichloroisocyanuric acid powder, chloric lime and other chlorine-containing disinfectants. If there are parasites such as fish, leeches, etc., use 0.7～1.2 mg/L copper sulfate or 0.3～0.5 mg/L refined trichlorfon to spray to kill the fish and leeches. Use 2.5%salt water bath to kill the leeches. , To prevent them from becoming the transmission vector of the carp spring virus; select varieties with strong resistance; if the temperature is controlled, the water temperature can be adjusted to above 22 ℃.
(2) Gill rotten disease:clear pond silt, apply organic fertilizer to fully ferment, use potassium permanganate or salt solution medicine before fish seeding in pond bath. When the disease occurs, the following measures can be taken for treatment:quicklime or chlorine-containing disinfectant solution is splashed into the whole pond; Sanhuang powder, Rhubarb powder, etc. mixed feeding; florfenicol or compound sulfamethazine powder mixed feeding.
(3) Water mold:remove the thick silt of the pond, disinfect with 200mg/L quicklime or 20mg/L bleaching powder; avoid fish body injury during operation; Before and after stocking, the fish species that have been transported over long distances should be disinfected with 2%to 3%salt water; after the broodstock is artificially reproduced and injured, apply 10%potassium permanganate solution to the wound for disinfection. When sick, soak the diseased fish with a concentration of 20mg/L povidone-iodine solution for 20-30 minutes; use 8mg/L salt and baking soda mixture (1:1) to splash the whole pond.
(4) Cucurbita vulgaris:prevent wild fish from entering the aquaculture water body. Fish ponds with Cucurbita vulgaris disease should be cleared of excessive silt and cement pool walls Wash, disinfect with quicklime or bleach, and expose to the hot sun for 1 week. When the disease occurs, it should be soaked in salt water with a salinity of 20∽30, or splashed with a solution of copper sulfate and ferrous sulfate powder with a concentration of 0.7mg/L. It can also be sprinkled with boiled water with dried chili and ginger.