Common diseases and their control in loach farming
Through several years of investigation and practice, Jishan Huayao sorted out the common diseases that appeared in loach farming, and summarized the causes, symptoms and prevention methods for everyone's reference.
1 Erythroderma
1.1 Cause: Caused by Pseudomonas luminesces. It mainly occurs during the high temperature season, and the higher the water temperature, the more serious the infection, and the higher the mortality rate.
1.2 Symptoms: The loach first peels off the fins or part of the body surface, appearing grayish-white, the muscles begin to rot, the part becomes red, and then blood spots appear in these areas, and gradually become dark red. In severe cases, the surface of the sick loach is congested and inflamed, the fins, abdominal skin and anus are congested and ulcerated; the caudal fin and pectoral fin are engorged and rotted; the tissue between the fins is often destroyed in the shape of a broom, and is not fed until death.
1.3 Prevention and control methods: (1) to avoid loach injury, the seedlings should be washed and disinfected in a salt water bath of 3% to 4% for 5 to 10 minutes before stocking. (2) Sprinkle with 1g/m3 bleaching powder whole pool or 0.2g/m3 dibromohydantoin whole pool for 3 to 4 days. (3) Five-fold seeds, 4g per cubic meter of water, grind the five-fold seeds and soak them in boiling water, and sprinkle the whole pool once every 15d during the epidemic season. (4) Rhubarb, 2.5 ~ 3.7mg / L, first soak the rhubarb with 20 times the weight of 0.3% ammonia water to improve the effect, and then connect the water with slag, the disease epidemic season every 15 days of the whole pool sprinkled once. (5) Fresh toad crisp 10g, stirred in cool water, sprinkled in the whole pool, the concentration is 0.5mg/L, every 3d1 times. (6) Castor fresh stems and leaves 15kg bundled into several bunches, placed around the pond soaking, each soaking for 3 to 4 days, 2 times in a row, can prevent and control the disease. (7) Each mu of water surface is fried with 0.5kg perilla and 250g of dry powder, and sprinkled all over the pool.
2 Bacterial gill rot disease
2.1 Cause: Caused by Columnar Flex. This disease occurs all year round in all loach-raising areas in the country, generally starting when the water temperature is above 15 ° C, and the higher the water temperature at 15 to 35 ° C, the more likely it is to erupt and circulate, and the shorter the time to death. The more pathogenic bacteria in the water, the greater the density, the smaller the resistance of loach, the worse the water quality, and the more prone to outbreaks.
2.2 Symptoms: individual loach body color is black, especially the head, swimming slowly to respond to external stimuli, breathing difficulties, loss of appetite. The gills are rotted and whitish, the tip cartilage is exposed, the gills have sludge, mucus, and in severe cases, the gills have transparent holes.
2.3 Prevention and control methods: (1) The quicklime is thoroughly cleared and disinfected or the whole pool is sprinkled with quicklime to make the pool water appear at a concentration of 25g/m3. (2) When stocking fish fingerlings, soak them in 10 to 20 mg/L potassium permanganate solution for 15 to 30 min, or soak them in 2% to 3% salt water for 5 to 10 min. (3) Feed with rotten gill spirit loose mix bait, 1g per kilogram of body weight (according to 5% of the amount of bait, 20g per kilogram of feed), once a day, for 3 days. (4) The combination of external use and internal use is better. Topical oxytetracycline 3 ~ 5g / m 3 water medicinal bath, internal administration of oxytetracycline 1g mixed with 1kg of feed, the bait is 1 time / day, 4 ~ 6d can be.
3 Rotten fin disease (also known as redfin disease, rotting skin disease)
3.1 Cause: Caused by Aeromonas hydrophila. Deterioration of water quality and inadequate storage are most likely to induce the disease. The disease is endemic in summer and has a higher incidence.
3.2 Symptoms: The sick loach fin, abdominal skin and anus are congested and ulcerated, the caudal fin and pectoral fin are whitish and ulcerated, and the sides of the fish body are puffy from the head to the tail, and there are erythema. Loach is unintended and weakens to death.
3.3 Prevention and control methods: (1) Thoroughly clear the pond before releasing the seedlings, and carry out strict disinfection of the fish body when the loach seedlings go down the pond, which can reduce the occurrence of this disease. (2) Sprinkle with 0.2g/m3 dibromohydantoin whole tank for 3 to 4 days. (3) Mix and develop a medicinal powder with large green leaves, five-fold seeds, ground brocade grass, black oak and garlic in the ratio of 3:2:1:2:2, and add 50 to 100g of medicinal powder per kilogram of feed to mix and feed well, 2 times / day, continuous feeding 5 ~ 6d. (4) Sprinkle with 0.4g/m3 strong chlorine whole tank, use 2 times in severe cases, and mix into "florfenicol" according to the specific weight of the feed for 5 to 7d.
4 Hemorrhagic diseases
4.1 Cause: induced by a combination of factors. The disease occurs from early spring to October, with the highest incidence in summer.
4.2 Symptoms: The surface of the loach body is a bit or blocky congestion, the larynx and abdomen are more obvious, and sometimes the mouth and eyes are bleeding. The disease is highly contagious and spreads rapidly, and is suspected of bacterial sepsis.
4.3 Prevention and control methods: (1) Improve the breeding environment, remove the remaining bait in time, and prevent the deterioration of water quality. (2) Sprinkle quicklime once a half-month on the whole pond, and the dosage is 25~30g/m3.
5 Printing disease
5.1 Cause: Caused by the punctate subspecies of P. aeromonas.
5.2 Symptoms: The lesions on the loach body are puffy, oval or round, and the red affected part is mainly on both sides of the tail stem, which seems to be stamped, and is mainly popular in July to September.
5.3 Prevention and control methods: (1) Sprinkle the whole pool with 1mg/L bleaching powder. (2) Sprinkle with 0.3mg/L bromochlorohydantoin whole tank. (3) 2 to 4mg/L of the pentaploids are sprinkled throughout the pool. (4) Alternate treatment with bleach powder and bitter ginseng, on the first day, 1.5g of bleaching powder is sprinkled with each cubic meter of water; the next day, each cubic meter of water is boiled with 5g of bitter ginseng into a solution, sprinkled in the whole pool, used alternately for 3 consecutive times, and the drug is used for 6d. (5) Use 5kg of mugwort root to mash the juice, add lime 1.5kg/mu, mix well and add an appropriate amount of water to sprinkle the whole pool.
6 Water mold disease
6.1 Cause: Loach is mechanically damaged during fishing or transportation, and the wound is caused by a variety of water mold and cotton mold infection. The disease can occur throughout the year, with the highest probability of occurring in early spring and late winter. Fish eggs and seedlings are also highly susceptible to occurrence during human hatching.
6.2 Symptoms: Mainly manifested in the initial stage of the naked eye can not see the symptoms, a few days later the naked eye can see clusters of white or gray cotton flocculents at the site of the disease. Sick loach is slow, loss of appetite, and emaciation to death.
6.3 Prevention and control methods: (1) Mechanical damage should be avoided as much as possible during capture and transportation, and 3% to 4% salt water bath should be used for 5 to 10 minutes before seed stocking. (2) Sprinkle the whole pool with a mixture of 0.04% baking soda and table salt (1:1). (3) Each mu of water surface is beaten with 2.5 to 5 kg of calamus and 0.5 to 1 kg of salt into a pulp, add 2 to 5 kg of human urine, and sprinkle the whole pool. (4) The five-fold mash is completely dissolved in warm water, and the whole pool is sprinkled, so that the concentration of the pool water is 4mg/L. (5) 10kg of tung leaves or sesame seeds per acre of water surface, tied into small bundles and put into the pool. (6) The whole pool is sprinkled with water mold net 0.6~ 0.75mL/m3. (7) Loach eggs: use 400g of salt plus 400g of baking soda solution per cubic meter of water to bathe for 1 hour for prevention and treatment.
7 Enteritis
7.1 Etiology: Caused by enteric punctate aeromonas infection. Generally from loach to adult loach can be diseased, the water temperature above 20 ° C when the epidemic began to circulate, the peak of the epidemic water temperature of 25 ~ 30 ° C, this disease is often associated with bacterial gills, red skin and other diseases.
7.2 Symptoms: The loach moves slowly, stops feeding, the loach body turns blue, the head appears special, erythema appears in the abdomen, the intestinal tube is hyperemic and inflamed, the anus is red and swollen, the abdomen has blood and yellow sheath mucus flowing out, and the heavy one becomes purple and dies quickly.
7.3 Prevention and control methods: (1) Keep the pond water fresh, feed the bait and adhere to the "four certainties" principle. (2) Add "fish with multi-dimensional" mixture to feed according to 5% of body weight, and feed for 3d. (3) The method of "internal and external treatment" of internal medicine and sprinkling disinfectant throughout the pool is adopted, and the external medicines include bleaching powder, strong chlorine, chlorine dioxide, etc.; internal use can be used for composite fishing drugs such as "enteritis treasure" and "fisherman's delight", or every 10kg of fish with garlic 50g mashed and mixed into feed feeding, once a day.
8 White tail disease
8.1 Cause: Caused by Pseudomonas albicans.
8.2 Symptoms: The initial loach seedling tail stalk is gray, then extends to the entire body surface behind the base of the dorsal fin, and turns from grayish white to white, the loach seed is head down, tail is up, perpendicular to the surface of the water, in severe cases the tail fin partially or completely rots, and soon dies. May to July every year for the epidemic season, mainly manifested in the summer flower pond before and after, when the summer flower has a large number of wheel worms and other protozoa invasion parasitism, so that the loach body is injured, the injured loach is susceptible to infection, and the mortality rate can be as high as 30% to 50%.
8.3 Prevention and control methods: (1) Add 25 times the weight of 0.3% ammonia water to soak, and sprinkle the whole pool with juice and slag, so that the water concentration is 3mg/L. (2) Add 1kg of dried black oak leaves (combined with 4kg of fresh products) to 20 times the weight of 2% quicklime water and soak for 24 hours, and then cook for 10 minutes and then sprinkle the whole pool with residue, so that the concentration of pool water is 4mg/L. (3) Bleaching powder (30% effective chlorine) is dissolved in water, and the whole pool is sprinkled, so that the concentration of pool water is 1g/m3. After 4 hours, sprinkle the five-fold soaking solution (soaked in boiling water after grinding) to make the concentration of the pool water 3g/m3 to promote rapid healing of the lesion. (4) Purify with poison (univariate stability chlorine dioxide), the dosage per cubic meter of water is 0.15g, the whole pool is sprinkled, once a day, and severe cases can be used 2 to 3 times; at the same time, enrofloxacin powder and multi-dimensional, 0.2g and 0.05g per kilogram loach are mixed and fed, 2 times a day, and used for 5 to 7 days.
9 White body red ring disease
9.1 Cause: Caused by long-term storage after loach capture.
9.2 Symptoms: The surface of the sick fish and the fins are grayish-white, and the body surface appears red rings, and the affected area ulcers in severe cases.
9.3 Prevention and control methods: (1) After the loach is stocked, the water body is sprinkled with 0.2mg/L of "Hundred Poison Qing"; (2) the whole pond is sprinkled with "bacterial enzyme stress spirit" and the diseased fish are moved into the still pool for temporary breeding for a period of time, which can play a better effect.
10 Bubble disease
10.1 Cause: Caused by excessive oxygen or other gas content in water, mainly endangering fry.
10.2 Symptoms: Loach floats on the surface of the water, the belly bulges like bubbles, this disease is most likely to occur in the loach stage.
10.3 Prevention and control methods: (1) Aeration is carried out before adding water to fully degrade the organic matter in the water. (2) Strengthen daily management, reasonable feeding, and prevent water quality from deteriorating. (3) When the disease occurs, immediately add fresh water, and sprinkle the whole tank with salt solution, the dosage is 4 ~ 6kg/ mu. (4) Appropriately improve the pH and transparency of the water body after the onset of the disease, which has a good alleviating effect.
11 Flex bone disease
11.1 Cause: Caused by abnormal water temperature during incubation and lack of vitamins.
11.2 Symptoms: The loach vertebrae are curved and small.
11.3 Prevention and control methods: maintain a good incubation water temperature and add various vitamins to the future feed.
12 Wheelworm disease
12.1 Cause: Caused by rotifer parasitism. It is endemic in all loach-raising areas in China, which mainly endangers loach seedlings and loach species, and can cause a large number of deaths when severe.
12.2 Symptoms: Wheelworms generally parasitize the gills and body surfaces of loaches. Loaches become ill and eat less and swim alone. In severe cases, the insect body is densely packed, and if it is not treated in time, it will affect growth at worst and cause death at worst. The popular season is from May to August.
12.3 Prevention and control methods: (1) Thoroughly clear the pond with quicklime before stocking. (2) Sprinkle with copper sulfate and ferrous sulfate (5:2) mixture (0.7g/m3) in the whole tank. (3) 1m water depth per mu, sprinkle the whole pond with 30kg of boiling water with neem branches and leaves, or use 2kg of leeks per mu with 500g of salt to grind into pulp to feed the fish. (4) According to the pool water per cubic meter with crystal enemy insects 0.7g of the whole pool. (5) Sprinkle with the whole pool of "wheel speed net".
13 Gymuscosis
13.1 Cause: Caused by parasitism of the tongue cupworm. It can occur all year round, and is more common in May to August.
13.2 Symptoms: Parasitizing the loach's skin or gills, usually ingesting food in the surrounding water for nutrition, has little effect on loach. However, if a large number of loach seedlings are parasitized, it will cause breathing difficulties and cause the loach seedlings to die in severe cases.
13.3 Control methods: (1) Soak with copper sulfate solution (8g/m3) for 15 to 20 minutes before seed stocking. (2) Sprinkle with copper sulfate and ferrous sulfate (5:2) mixture (0.7g/m3) in the whole tank.
14 Three generations of insect diseases
14.1 Cause: Caused by three generations of parasites. It is mainly prevalent in May-June and is more harmful to seedlings.
14.2 Symptoms: Parasitism on the loach body surface and gills. Parasitic loach seedlings often float on the surface of the water, are restless, or spin on the surface of the water. The skin of the sick loach body has a grayish-white mucus membrane that loses its original luster. At the same time, the appetite is reduced, the fish is emaciated, and it is difficult to breathe. Close inspection of the naked eye reveals the worm body.
14.3 Prevention and control methods: (1) Using the soaking method, the small pool can be soaked in the whole pool, and the large pond needs to concentrate the loach in one corner, and the concentration of 20mg/L potassium permanganate solution is used to soak
15 to 25 minutes. (2) Sprinkle with 0.5g/m3 crystal enemy insects.
15 Lateral trematodiasis (commonly known as "closed mouth disease")
15.1 Etiology: caused by parasitism of lateral trematodes.
15.2 Symptoms: Infected loach growth arrest, after dissection can see a large number of trematodes accumulated in the fore intestine, there is no food in the intestine.
15.3 Control methods: clear ponds, thoroughly disinfect them, and eliminate snails and other wild fish.
16 Biological predators
16.1 Predators: Loach has many biological predators, mainly frogs, aquatic insects, birds and ferocious carnivorous fish, especially bird pests.
16.2 Prevention and control methods: (1) remove weeds by the pond, maintain the environmental hygiene of breeding, strictly prevent frog invasion, find frogs should be caught in time, frog eggs should be salvaged in time. (2) The inlet should be blocked with an iron screen to prevent wild and miscellaneous fish from entering the pond with the flowing water. (3) Do not let the birds approach the loach pond, and find that the birds approach the loach pond in time to drive away.
In short, in the process of loach breeding, especially in large-scale aquaculture, we must attach great importance to the prevention and control of loach diseases and insect pests, so that there is timely treatment of diseases, disease-free active prevention, to ensure that the water source is clean, only scientifically, ecologically and healthily carry out loach breeding work, in order to achieve the purpose of increasing production and income, increasing economic benefits.