Prevention and treatment of common diseases of California perch
1. Bacterial diseases
1. Gill rot disease
【Pathogen】The pathogen is Flavobacterium colunmnari. The body is elongated, curved or straight, rod-like, without flagella, and negative for Gram staining.
【Popular characteristics】It is generally popular from April to October, and is most popular in summer. The onset of the disease begins above 15 °C and begins to circulate above 20 °C. In the range of 15-35 ° C, the higher the water temperature, the faster the onset of the disease and the shorter the time of death.
【Main symptoms】The diseased fish is slow in movement, unresponsive, often swimming alone in isolation, and the body color is black, especially the head. Opening the gill cap of a diseased fish, it is often seen that the inner epidermis of the gill cap is often hypergly bloody. The gill filaments are swollen, often with white or earthy yellow mucus, and in severe cases, it can be seen that from the end of the gill filament, it rots evenly along the edge of the gill flap. The end of the lip is inflamed, hyperemic, and eroded.
【Prevention】
(1) Before the fry go down to the pond, use a 2-4% salt water medicinal bath for 5-10 minutes.
(2) Strong chlorine is sprinkled in the whole pool, and the dosage is 200-300g/mu. Rice, once a day, 1 to 2 times.
(3) Bromochlorohydantoin whole tank spilled, (in terms of bromoclohydantoin), 20-30mg/mu. rice. Once a day, in severe cases, use 2 times.
(4) When optionally (2) (3) a measure is spilled externally, norfloxacin is taken internally, (in terms of norfloxacin) 15-20mg per kilogram of fish per day; or use sulfonamides to mix bait for 3 days.
2. Leukoderma
[Pathogen] The pathogen is Pseudomonas dermoalba, which was once called Pseudomonas dermoalba, which was once called P. albicans. Most are concatenated, extremely single or double flagella, motility, no spore, no capsular membrane, negative Gram stain.
【Epidemic characteristics】Water temperature above 25 °C is the epidemic season, generally infected with fry below 5cm and summer flower stage, 2 to 3 days after the onset of the disease will cause a large number of deaths; every year from June to August is the epidemic season, especially in the summer flower pond before and after the operation is careless, causing mechanical damage to the fish body or a large number of protozoa parasitism such as wheel worms on the body surface, the fish body is injured, the pathogenic bacteria take advantage of the weakness, resulting in infection outbreaks.
【Main symptoms】In the early stage, the caudal stalk becomes whitish, and as the disease progresses, the body surface from behind the base of the dorsal fin is all whitish. In severe cases, the caudal fin is ulcerated and mutilated. The sick fish died soon after.
(1) Thoroughly clear the pond, and use 20kg/mu of dry biological bottom Kang fungus to treat the bottom of the pond.
(2) Select high-quality healthy seedlings. Before the fish are planted in the pond, use a 2 to 4% salt water medicinal bath for 5-10 minutes.
(3) In the process of fishing and transportation, avoid injury to the fish body; kill it in time when there is a parasite on the surface of the fish body.
(4) Strong chlorine is sprinkled in the whole pool, and the dosage is 200-300g/mu. Rice, once a day, 1 to 2 times.
(5) External pouring at the same time as internal administration of thiamphenicol or florfenicol, continuous use for 3 to 5 days.
3. Enteritis disease
【Pathogen】The pathogens are Aeromomas hydrophila, A.caviae guinea pig, Aeromonas punctuatea intestinalis (Aeromonas puncta f. intestinalis) and so on. Extreme single flagella, motility, no spores, Gram-negative short bacillus, blunt circles at both ends.
【Popular characteristics】It occurs all over the country. The prevailing water temperature is above 18 °C, and 25 ~30 °C is the peak of the epidemic. Occurs from fingerlings to adults.
【Main symptoms】 Open the belly of the fish, early can be found that the intestinal wall is congested and red, swollen and inflamed, there is no food in the field or only a small amount of food in the posterior part of the intestine, and there is yellow mucus in the intestine. In the later stages of the disease, the whole intestine can be seen to be congested and inflamed, the abdomen is swollen, there is ascites, the anus is often red and swollen, and the abdomen is lightly pressed or the head is lifted, that is, there is yellow mucus or blood pus flowing out of the anus.
(2) Select high-quality healthy seedlings. Before the fish species are laid out in the pond, soak with 8 to 10 mg/L bleaching powder for 15-30 minutes.
(3) In the process of breeding, keep the water quality clean, and use the dry boundary bottom net tablet every 15 days to adjust the water quality with excellent water bacteria and composite photosynthetic bacteria.
(4) Use amide alcohol drugs for treatment, 2 to 3 times a day per kilogram of fish body weight, each time the bait is fed thiamphenicol powder (specification of 100g: 5g) 0.35g, for 3-5 days; or use Qianjie intestinal Kang 120 or compound lactic acid bacteria according to 2% mixing bait feeding; or use the dry boundary biological Clostridium butyrate mixing bait feeding, the use method is 80kg-100kg/250g of mixing, continuous use for 3-4 days.
4. Ulcer syndrome
[Pathogen] The pathogens are Aeromomas hydrophila and Aeromonas puncta f. punctta. The isolated strain is Gram-stained negative bacilli, rounded at both ends, mostly two connected, extremely single flagella, motility, and no spores.
【Epidemiological characteristics】The disease is more common from December to April of the following year, and the target of harm is mainly adult fish, and it is easy to infect the pathogen after injury, resulting in the onset of the disease.
【Main symptoms】 There are inflammatory lesions of different sizes on the side of the body, tail, abdomen, head and the base of the fins of the diseased fish, and the lesions are hyperemia and inflammation, the scales are shed, the epidermis and dermis are ulcerated, and the fish bones can be seen in severe cases. Lesions are mostly round or oval in shape and are accompanied by water mold.
(2) In the process of breeding, the mixture is fed to the multi-dimensional stress spirit of the dry world organism, 80-100kg/500g, which improves the immunity of the fish body.
(3) In the fish pond where the disease occurs, the medicinal bath is sprinkled with povidone iodine solution or chlorine dioxide and other whole ponds.
(4) Enrofloxacin or florfenicol for treatment while pouring medicinal bath externally; after healing, use Dry Boundary Biological Compound Lactic Acid Bacteria or Clostridium butyrate to adjust the balance of intestinal flora and enhance immunity.
5. Bacterial sepsis
[Pathogen] The pathogen is Aeromomas hydrophila. The same genus of mild aeromonas, aeromonas guinea pig, Schubert aeromonas, etc. also have certain pathogenicity. Aeromonas hydrophilus is a gram-stained short bacillus, single or paired or short-chained, extremely single flagella, motility, no spores and capsules.
【Epidemic characteristics】From summer flower fingerlings to adult fish can be infected, can occur in intensive ponds, cages and reservoirs and other culture patterns are prevalent from March to November, peak period from May to September.
【Main symptoms】In the early stage of the disease, the upper and lower jaws, mouth, gill caps, eyes, fins and sides of the fish body are mildly hyperemia, less food in the intestine, and some fish also have symptoms such as scale erection, muscle congestion and congestion in the posterior chamber of the bladder wall. Severely ill fish are anorexic or uneaten, stationary or paroxysmal, and some rub against the edge of the pool, and finally die of exhaustion.
(1) Thoroughly clear the pond, remove the sediment, and use 20kg/mu of dry biological bottom Kang bacteria to treat the pond bottom to improve the ecological environment of the water body.
(2) Select high-quality healthy seedlings. Before the fish species descend into the pond, use a medicinal bath of 15 to 20 mg/L aqueous potassium permanganate for 15-30 minutes.
(4) Sprinkle with 0.2~0.3mg/L trichloroisocyanuric acid whole tank or sprinkle with benzalkonium bromide whole tank for disinfection treatment.
6. Nocardiosis
【Pathogen】The pathogen is mainly caused by Nocardia infection, short rod-like or slender branches, slow growth, positive Gram stain, no motility, and white sand particles on blood plate medium.
【Epidemic characteristics】Diseases that have occurred frequently in recent years, from May to July as the epidemic period, are mainly harmful to adult fish, and the morbidity and mortality rate are high, and seriously affect the commodity value of adult fish.
【Main symptom】 The sick fish has lost appetite, swims alone on the surface of the water or the edge of the pool, and the body color becomes black. Anatomical observation, the spleen, kidney, liver, mesentery, bladder and other places are covered with small white dots, similar to nodules.
In severe cases, the kidneys, cheek rakes and muscles have large white bulging pustules, and after dissection, white or reddish blood pus flows out, that is, decayed muscle or fat tissue mixed with blood cells and nocardia to form.
There are two types of fish infected with Nocardia infection: gill nodular type and trunk nodular type.
(1) Gill nodule type: a large milky white nodule is formed at the base of the gill filament, and the gills are obviously faded.
(2) Trunk nodule type: ulceration occurs in the subcutaneous fat tissue and muscle of the trunk, and the appearance is a nodule of different sizes and irregular shapes. There are also nodules in the heart, kidneys, spleen and swim bladder. There is an inflammatory response at all lesions.
(2) In the process of breeding, keep the water quality clean, and use the dry boundary bottom net tablet every 15 days to adjust the water quality with euhydrogenous bacteria and composite photosynthetic bacteria.
(3) Strengthen feeding management, regularly add dry biological multidimensional stress spirit and compound lactic acid bacteria to improve immunity and enhance disease resistance.
(4) Use enrofloxacin and norfloxacin and other drugs that have inhibitory effects on gram-stained positive bacteria.