Second, the spores of crucian carp must have "water earthworm" as the intermediate host to reproduce (the latest authoritative information). The best medicine to kill earthworm is trichlorfon once a month.
Third, mature spores are difficult to kill under the premise of fish safety.
4. Sporozoa belongs to protozoa, which mutates rapidly and is easy to form drug resistance.
5. Copper sulfate is usually effective for protozoa and sporozoites.
Sixth, crucian carp is strong and not easy to get sick.
Seven, treatment and disease prevention I suggest the use of trichlorfon, copper sulfate mixture, or add other pesticides without compatibility contradictions to enhance the effect, the drug effect lasts for more than 72 hours, completely killing earthworm mature spores and water. There are chlorpheniramine hydrochloride, diclazuril and artemisinin in fish. However, oral drugs alone cannot prevent the disease, and topical pesticides are also half the effort.
Eight, if you are in the main producing area of crucian carp, sporozoite flooding area, then I suggest you rotate other varieties. Because this disease will definitely seriously affect your breeding plan. Even if you don't get sick, frequent medication will affect the growth rate of fish. This may be an important reason why you are still young when fish prices are high.
How should crucian carp farmers control myxosporosis of crucian carp
Sarcocystis in the throat of crucian carp is very serious in Liaoning and Jiangsu, and farmers call it "laryngeal cancer" and "swollen eyes". Box carp also happens from time to time. The disease began to occur at the beginning of Tang Qian's summer flower cultivation, and should be controlled at the beginning of summer flower cultivation. The method is to spray spore bacteria mixed with soybean milk or aquatic yeast, and then feed them with 1mm, 2mm and 3mm respectively when feeding granular feed.
First, the epidemic. Myxosporidiasis of crucian carp mainly harms 1 year-old fish and adult fish, and the incidence of summer fish is less, and it is often prevalent every April ~10, especially from June to August. The infection rate of disease pool is generally 30-80%, and the mortality rate is generally around 20%, which causes great economic losses.
Second, the main symptoms. Myxosporidia parasitize fish scales, gills, skin and fins in the form of cysts. The diseased fish are black and thin, and their foraging ability is poor. It floats near the surface of the water and swims slowly, sometimes for a while. Pustular circular spots appeared on the surface of myxosporidia parasitic fish; Parasitic under fish scales will form cysts. As the cyst gradually increases, the scales of the diseased fish will stand up to varying degrees, resulting in swelling of the body surface and some muscles festering. Parasitic on gills, mucus increases, gill filaments rot and swell; Parasitic in the brain, white cysts can be seen in the anatomical parasitic parts.
Third, prevention and control methods. (1) When cleaning the pond, dig out excess silt, and then thoroughly disinfect it with quicklime or chlorine-containing disinfectant to kill the overwintering cysts in the pond. (2) Do a good job in the quarantine of larval fish, and don't enter the fish from the area with high incidence of Myxosporidia. Before releasing fish, soak the fish with potassium permanganate or the mixture of trichlorfon and copper sulfate to kill Myxosporidia and prevent Myxosporidia from entering the pool with the fish. (3) Deal with dead fish in time. Dead fish suffering from myxosporosis should be taken out of the pond and buried in time to prevent worm spores on the surface of dead fish from being scattered in the pool water and infected by other fish. At the same time, tools that have been exposed to sick fish should be soaked in concentrated lime water or mixed solution of 0.5g/m2 crystal trichlorfon and 0.5g/m2 copper sulfate to prevent reinfection. ⑷ Feed high-quality bait, strengthen management and enhance the disease resistance of fish. At present, there is no ideal specific medicine. The mixture of 0.5 g/m3 crystal trichlorfon (containing 90%) and 0.5 g/m3 copper sulfate is commonly used at onset, and it is sprayed evenly for 3-4 times in the whole pool, with an interval of about 5 days each time. 5. Take 0. 1.5-0.2% levamisole hydrochloride or 0. 1.5-0.2% chlorpheniramine hydrochloride as bait for 5 days.