Culture technology of seven-star fish

Seven-star fish scientific name snakehead (l fish), for the snakehead family snakehead is a freshwater fish, also known as solitary, mountain flower fish, mountain grouper, etc., such as snakehead, through the in-depth research and domestication of scientific and technological workers in Guangxi, Jiangxi, Hubei and other places in China, has been gradually transformed into an artificial breeding species, with important edible value, medicinal value and economic value, let's take a look at the seven-star fish culture technology!

How much is the seven-star fish per jin?

The market price of seven-star fish is much more expensive than other fish, usually with an average price of more than 30 yuan per jin. But now there is basically no pricing on the market, because there are too few people to raise, and this kind of fish is seldom sold on the market, and it is generally directly ordered by restaurants and clubs. The seven-star fish is distributed in wild in all the river systems south of the Yangtze River in China, and it is relatively common in the upper reaches.

Growth habits of seven-star fish

The seven-star fish is a wide-temperature fish with strong adaptability, the living water temperature is 1: 38 ℃, the feeding water temperature is 12: 32 ℃, the growth water temperature is 13: 30 ℃, and the best growth water temperature is 15-28 ℃. It has the living habits of dark, burrowing, burrowing, collective living and remnant food. Like to live in mountain streams, but also live in rivers, ditches and ponds and other water bodies. Ferocious, rapid action, for animal omnivorous fish, to fish, shrimp, aquatic insects and other food, in artificial domestication conditions like to eat formula feed and frozen fresh fish.

Breeding techniques of Seven-star Fish

The age of first sexual maturity of seven-star fish is 2 winter years old, and that of cultured fish is 1 winter age, the relative number of eggs is about 500 eggs, the reproductive period is from April to June, the spawning period is from May to July, and the breeding water temperature is 18-28 ℃. Spawn many times a year, there are oil balls in the yolk, floating eggs. The testis is close to the ventral side of the swim bladder and the brown breeding season. The female and male parent fish chase each other in estrus, the female ovulates, the male ejaculates on the egg, and the egg gathers and floats on the surface. Parent fish have the instinct to protect their eggs until they hatch. The fry emerging from the membrane had an upward abdomen and could swim in groups on the 4th day after hatching, and on the 25th day their morphology and living habits were the same as those of adult fish.

Culture techniques of seven-star fish

1. Fish pond construction: fish ponds should be selected in places with sufficient water sources, good water quality and convenient drainage and irrigation. Ponds, cement ponds, pit letters, rice fields, lotus root fields, cages and so on can be cultured, but ponds are the best. As the seven-star fish like to be afraid of light, tile tubes or bamboo tubes should be placed at the bottom of the pond for fish habitat. There should be fish blocking at the inlet and drain, and the pond base should be surrounded by polyethylene mesh with a height of more than 50 cm to prevent the enemy from invading or fish escaping.

2. Seedling restocking: the fry of Seven Star Fish are required to be disease-free, injury-free, physically strong and neat in specification. Fish fry with a body length of less than 5 cm shall first be cultured in a cement pond with an area of less than 10 square meters and a water depth of 20 cm to 50 cm. 2000~50O0 tails of fish fry with a body length of 2 cm can be placed per square meter. When the fry grows to the specification of more than 5 cm in body length, it can be transferred to a large pond for culture, with 20 to 50 fry per square meter and up to 100 fish high.

3. Feed selection: seven-star fish is a typical carnivorous fish, which likes to eat animal feed. The fry stage (body length less than 4cm) is mainly fed to water fleas, harvest worms, water earthworms, minced meat, egg yolk and so on. With the growth of fish eating habits have also changed, animal and plant feed can be eaten, but still prefer animal feed. Animal feed includes earthworms, maggots, Tenebrio Molitor, mussel meat, silkworm pupa, fish and shrimp, animal meat and viscera, etc. In the lack of animal feed, also eat plant feed, such as corn meal, peanut wheat flour, bean dregs, rice, noodles and so on.

4. Feeding and feeding: the seven-star fish fry stage is fed with powdered formula feed (preferably crushed by a micro-crusher to crush the viscous feed). The crude protein content is required to be 40% 45%, and the crude protein content is 38% to 42% after the feed grows to 10 cm. No matter what kind of feed is fed, the fish should be fed regularly, quantitatively, qualitatively and positionally, and a table should be set up in the pond. The daily feeding amount should be determined according to the water temperature, weather changes and the feeding situation of the fish, which is generally 3-10% of the fish's body weight, twice a day, 8: 9 a.m. and around 6 p.m. Feed should be fed in an appropriate amount, and the fish should be satisfied to prevent the remaining feed from polluting the water quality.

5. Water quality management: keep the water quality clean during the breeding period, change the fresh water regularly, account for up to half of the pool water each time, and discharge the dirt and residue in time. Water hyacinth should be planted in the pond, accounting for about 1/2 of the water surface, and the water hyacinth should be fixed in a certain position with bamboo poles, wood strips or ropes. In the hot season, the pool water should be properly deepened. The cement pool surface had better set up an Arbor or shade with a black shade net.

Prevention of fish disease in seven-star fish

1. Pond cleaning and disinfection: first remove the silt from the fish pond. seven to eight days before the fish pond, each mu of pond is disinfected with 190 kilograms of quicklime, or 4 days before entering the pond, 10 grams of bleach is used to disinfect every cubic meter of water.

2. Fish body disinfection: disinfection must be carried out first when the fish are released. Use 3% salt water for 3 minutes or 15~20ppm potassium permanganate for 15 minutes for 20 minutes. The bathing time should be controlled flexibly according to the tolerance of the fish.

3, tool disinfection: the method is to be exposed to the sun for one day, or you can disinfect it with medicine, such as soaking in 50ppm potassium permanganate or 200ppm bleach or quicklime for 5 minutes before use.

4. Feed disinfection: rinse the fresh feed, then soak it in 50ppM potassium permanganate or 100~200ppm bleach for 5 minutes, or soak in 20~200ppm chlorine dioxide solution for 10 minutes for 20 minutes, or feed organisms in 0.01~0.1ppm chlorine dioxide solution for 8 hours to 3 days before feeding the fish.

5. disinfection of the food farm: during the epidemic season of fish disease, every 7 to 15 days, after eating the fish, use 250g of bleach or 1000 g of quicklime and add an appropriate amount of water to dissolve and pour it near the food ground.

6. Water quality management: in the process of breeding, we should often observe the water quality, change the water in time, or implement micro-flow water to keep the water quality good and prevent the water quality from deteriorating.

7. Drug prevention: in the fish disease-prone season, drug sprinkling and bait are used to prevent both inside and outside, so as to control the occurrence of fish disease. Sprinkle chlorine dioxide or quicklime or strong chlorine or bleach or copper sulfate and ferrous sulfate mixture alternately once a month. The bait is usually mixed with antibiotics, sulfonamides, furans and feed for 3 days.

8. Avoid damage: fish injury is easy to catch disease, so in the process of fishing, transportation and pool transfer, strict operation procedures, careful care, try to avoid damage to fish body to prevent bacterial infection.

Prevention and control of diseases and insect pests of seven-star fish

L. Dizziness

[symptoms] in the early stage of the disease, the diseased fish stopped eating, the body color was black, and clustered in the corner of the pond. In severe cases, he swam in the water, struggled sharply or swam wildly, and then sank to the bottom of the pool and died. The cause of the disease is not known.

[harm] dizziness is most common in fish fry before body length 4 centimeters, and the epidemic season is from March to July and from April to May. The disease occurs rapidly, spreads quickly, and the morbidity and mortality are more than 90%. It is the most harmful fulminant fish disease in the seedling stage.

[prevention] there is no treatment. Fish culture facilities and tools should be strictly disinfected. The live bait should also be sterilized before feeding. Fish eggs and fry are not imported from the affected farm. When changing water, water injection should not be too urgent, and the temperature difference of water temperature should not be greater than 2 ℃. After each change of water, sprinkle chlorine dioxide in time to make the pool water 5PPM, or sprinkle it with furazolidone of 0.4PPM throughout the pool, or sprinkle it with raw limed water to make the ph value of the pool water at 7-8.

2. Rotten meat disease

[symptoms] the body surface is patchy and congested, the scales fall off, and then the dermis ulcers, the festering place begins to show red, and then necrosis and whitening. In severe cases, it can rot to the muscle or bone road, and the tail fester and rot. It can happen everywhere on the body surface, and in severe cases it can spread all over the body.

[harm] Meat rot is more common in fish species and adults with a body length of more than 4 cm, and can occur throughout the year. After the onset of the disease, it is highly contagious, and its cross-infection is also serious. The disease spreads quickly, and the mortality rate is more than 50% if it is not treated in time, so it is known as the "red plague". The disease is easy to be caused under adverse conditions such as fish body damage, high culture density, deterioration of water quality or great change of water temperature.

[prevention and treatment] after purifying water with 5~10PPM chlorine dioxide or 0.3ppm, sprinkle it in the whole pond. If the condition is serious, sprinkle it again every two days. When the water quality deteriorates, the water purifying agent of 10PPM can be added. The whole pool was sprinkled with furazolidone to make the pool water 0.5~1PPM concentration.

3. Rotifer disease

[symptoms] after being parasitized by a large number of rotifers, the diseased fish did not eat, the body color became black and thin, the mucus increased, and a white membrane was formed on the body surface. Wander alone in the pool, often spin, and eventually die of exhaustion. It does great harm to the strain of seven-star fish. The pathogen is invisible to the naked eye, but microscopic examination is very obvious.

[prevention and cure] sprinkle with 0.7PPM copper sulfate in the whole pool. Sprinkle the mixture of 0.5PPM copper sulfate and 0.2PPM ferrous sulfate in the whole pool. Sprinkle with Melia azedarach leaf juice to make the pond water 30~45PPA concentration.

4. Edward's disease

[symptoms] the body of the diseased fish is black, the abdomen is dilated, there is no wound on the body surface, and sometimes the anus is red and swollen. Autopsy showed that the kidney was congested, enlarged, ulcerated, and the fishy-smelling fluid was squeezed out of the abdomen. The fish species in the diseased pond like to cluster in the corner of the pond.

The epidemic season of the disease is from May to September, the water temperature of the disease is 15-40 ℃, and the optimum water temperature is 25-30 ℃. It is more common in the fry and fingerling stage. The mortality rate of diseased fish is 30% to 60%. Fish ponds fed with earthworms for a long time are prone to this disease.

[prevention and treatment] the whole pool was sprayed with 0.3 ppm Baidujing or 2 ~ 5 10~20PPM chloramphenicol or 0.2-0.5PPM furazolidone for 2 days when the condition was serious. Add 30 grams of chloramphenicol to the bait per kilogram of fish every day and feed it for 5 days. 2 grams of norfloxacin and 20 grams of photosynthetic bacteria were added to each kilogram of feed for 5 days.