How to cultivate grass carp?

Grass carp, as a fish with large sales in the market, is also doing well in the market, so there are people who are interested in grass carp culture. after all, grass carp has a lot of room for appreciation in the future market. Grass carp culture is still relatively guaranteed, basically will not appear grass carp unsalable situation.

How to cultivate grass carp?

1. Pond conditions of grass carp

1. Pond conditions: the pond is required to be far away from the pollution source, with an area of 5 to 10 mu, a flat bottom, a loam soil with a little leakage, a sediment of 10 to 20 cm and a water depth of about 2 meters. Each pond should be equipped with a 3-kilowatt turbine aerator and a 4-inch water pump to prepare for timely water exchange and oxygenation.

2. Decontamination and disinfection: grass carp have more diseases, and the pond is more prone to epidemic. At the same time, the elimination of miscellaneous fish is an important measure to ensure the normal feeding of grass carp and save feed. The specific method is to sprinkle the whole pool with 100 kg quicklime pulp per mu in the case of dry pond (5-10 cm of stagnant water), or sprinkle it in the whole pool after dissolving with 10 kg of bleach in warm water, so as to completely kill the disease-causing bacteria.

3. Water quality requirements: the pH value of pond water is 7.5-8.5, the transparency of pond water is about 30 cm during the peak culture period (June-September), and the oxygen consumption of organic matter is 18-20 mg / L.

2. Stocking of grass carp seedlings

1. Seedling selection: grass carp should choose individuals with golden color, harmless appearance, lively and strong, weighing about 100 grams. At the same time, because the two major diseases of grass carp bleeding and enteritis are easy to infect the same year's fish species, 2-year-old seedlings should be the best in the selection of seedlings.

2. Fish stocking: grass carp species are generally stocked with 800 to 1000 fish per mu, with 100 silver carp fingerling ranging from 250 grams to 500 grams, not with or less with carp, in order to avoid grazing with grass carp. In addition, fish species should pay attention to body surface disinfection before entering the pond.

Ecological habits of grass carp

Grass carp generally like to inhabit the middle, lower and nearshore aquatic grass areas in rivers, lakes and other waters. With the habit of migrating rivers and lakes, sexually mature individuals lay eggs in rivers and reservoirs, and after spawning, parent fish and young fish enter tributaries and lakes, usually feeding and fattening in flooded shoal grasslands and flooded areas as well as water bodies attached to trunk and tributaries (lakes, streams, harbours, etc.). Winter spends the winter in the deep waters of the main stream or lake.

Grass carp is a typical herbivorous fish with lively temperament, fast swimming, often foraging in groups and gluttonous sex. It feeds on zooplankton in the fry stage, and feeds on insects, earthworms, algae and duckweed when it is young. When the body length is more than 10 cm, it completely eats aquatic higher plants, especially Gramineae plants. The types of plants eaten by grass carp vary according to the food base in the living environment.

How does grass carp reproduce

Grass carp (white carp) grass carp and several other domestic fish have similar reproductive conditions and cannot lay eggs in still water under natural conditions. The spawning site is generally chosen in the confluence of the mainstream of the river, the deep trough on one side of the bend, and the section of the river that suddenly tightens on both sides as the suitable spawning site. The reproductive season is similar to that of silver carp and earlier than that of herring and bighead carp. The reproductive period is from April to July, which is more concentrated in May. Generally speaking, when the river water rises early and fiercely, and the water temperature can be stabilized at about 18 ℃, grass carp will lay eggs on a large scale.

The reproductive habits of grass carp are similar to those of other domestic carp. The ovaries of grass carp that reach mature age overwinter in the developmental stage of Ⅲ throughout the winter (December to February). When the water temperature rises to about 15 ℃ from March to April, the Ⅲ oocytes in the ovary quickly develop to the Ⅳ stage and begin reproductive migration, and complete the development from the Ⅳ phase to the Ⅴ stage in the retrospective process. When it meets the stimulation of hydrological conditions suitable for spawning, it will spawn. Usually spawning is carried out in the water layer, and the fish body does not surface, which is commonly known as "stifling"; but when there are good reproductive ecological conditions, such as a sharp rise in the water level and accompanied by thunderstorm, female and male fish chase in the upper layer of the water. there is a "floating row" phenomenon of abdominal shivering. After fertilization, due to the swelling of the egg membrane, the diameter of the egg can reach about 5 mm, drift along the water, develop best at about 20 ℃, and hatch fish fry in about 30-40 hours.

Feeding and management of grass carp

1, feed feeding: mainly feed pellet feed, feed protein content of 28% 32%, auxiliary green feed. Feed feeding follows the principle of "pre-coarse and post-refined" and "four fixed and four look". It is generally fed twice a day, and it is appropriate to finish eating within 2 hours and feed 80% of grass carp. After feeding pellet feed continuously for a period of time, the pellet feed should be stopped for one week, and the raw grain feed should be fed at intervals. Usually pay attention to adding appropriate amount of vitamins and other drugs in the feed to avoid a large number of deaths caused by diseases such as hepatobiliary syndrome of grass carp.

2. Water quality management: correct use of aerator, sunny and windless weather from June to October, turn on aeration for 2 hours at 1: 3 pm every day, and increase oxygen in the early morning. Oxygen should be increased early on continuous cloudy days. Add new water to the pond at the right time, and adopt the method of "small row and small advance, changing water many times" to gradually control the water quality. From June to September, add fresh water once every 3-5 days, about 10 cm each time, and sprinkle it with 10-20 kg quicklime in the whole pool every 15-20 days.

3. Disease prevention and control: the method of "combination of pre-coarse and fine, fine green" was adopted to control the occurrence of grass carp hepatobiliary syndrome. Grass carp common diseases are red skin disease, Gill rot disease, enteritis disease, generally take internal and external splash treatment, external splashing is mainly bleach, chlorine dioxide and other disinfectants, continuous use for 3 days. Oral administration with "Sanhuang powder" bait is better, every 50 kg of fish reuse Sanhuang powder (rhubarb 50%, Phellodendron Phellodendri 30%, Scutellaria baicalensis Georgi 20% crushed powder and stir well) 0.3 kg mixed with flour paste and mixed into the feed for 3 days.

4. Timely fishing: timely catching and listing of large adult fish is an important measure for high-yield grass carp culture, the main purpose is to reduce the fish carrying capacity of the pond water and promote the rapid growth of pond fish in the later stage. It is usually caught once at the end of July and when the water temperature is low in the early morning.

How to prevent grass carp from getting sick

1. Grass carp hemorrhagic disease: this is a viral fish disease. Fish body surface is generally dark and slightly red, subcutaneous and muscle bleeding, oral cavity, lower palate, head or orbital congestion, and even exophthalmos, Gill cover, fin base hyperemia. The main symptoms are: hyperemia of body surface, Gill cover, muscle and intestinal tract. Sometimes the symptoms appear at the same time, sometimes there are only two kinds of symptoms, and the mortality rate is very high. The effect of povidone iodine sprinkling and oral administration of Chinese herbal medicine in the whole pool is obvious. The effect of immune prevention with vaccine is significant, and the injection of inactivated vaccine into fish can be prevented.

2. Gill rot disease of grass carp: bacterial disease, all kinds of grass carp are easy to occur. If the concentration of ammonia nitrogen and hydrogen sulfide in water exceeds the standard, chemical or biological methods should be used to reduce the concentration of ammonia nitrogen and hydrogen sulfide, and then apply medicine; sprinkle 150 g / mu of 8% chlorine dioxide, 250 g / mu of 8% bromochlorohydantoin and 250 g / mu of 10% povidone iodine per meter of water depth, and combine the method of adding vitamin C1 g, garlicin 1 g, enrofloxacin or florfenicol 2 grams per kg feed.

3. Grass carp enteritis: bacterial diseases, all kinds of grass carp are easy to occur. Spraying disinfectant and internal administration of allicin, antibiotics and other drugs are effective; prevention and treatment methods: every 50 kg of feed 10 grams of Litalin, made into bait feeding, once a day, continuous feeding for 5 days.

With the in-depth study of fish culture technology, there are more scientific techniques for cultivating grass carp, which greatly reduces the death of grass carp and greatly improves the survival rate of grass carp. and now grass carp disease prevention and control measures have been further improved, so reduce the probability of grass carp disease.