The key to raising yellow catfish well is disease prevention

The key work in breeding Pelteobagrus fulvidraco is to control the diseases and insect pests of Pelteobagrus fulvidraco. From the release of seedlings to the fishing of adult fish, it should be carefully managed.

First, make full preparations for winter.

1. Clear the pond and cultivate water. Every winter, after the fish species pass through the pool or adult fish out of the pond, drain the pond water, clean up the sludge at the bottom of the pond and trim the pond foundation, so that the pond is exposed to cracking, which can accelerate soil weathering and achieve the purpose of controlling and eliminating diseases and insect pests; at the same time, it is easy to remove weeds on the edge of the pond and reduce the damage of parasites and aquatic insects to fish species. The whole pond was disinfected with quicklime 755 kg ~ 150 kg per mu and crystal trichlorfon 1 kg ~ 1.5 kg per mu to completely kill the pathogen. After 5 ~ 7 days of disinfection, new water was injected and 200 kg of rotten manure was applied per mu to cultivate water. After 7 ~ 10 days, seedlings could be released when a large amount of plankton appeared in the pond.

two。 Bleach cleans the pond. The general bleach contains about 30% available chlorine and its dosage is 15 kg / mu. After the bleach is melted with water, it is sprinkled all over the pond. Generally, the drug power disappears completely after 4 ~ 5 days, and the fish can be released.

Second, the release of seedlings depends on the market

Large-size commercial Pelteobagrus fulvidraco is popular in the market, so about 30g / tail of large-size fish should be put into adult breeding. The stocking quantity of fish species can be flexibly controlled according to pond conditions, management level, feed supply and fish species specifications. Generally, about 1500 fish can be put in 30g / tail per mu, and about 50g / tail in silver carp. The fish released should be of neat specifications, bright color, smooth body surface, no disease, no injury, no defective fins, strong physique, and should be soaked in 5% salt water for 10 minutes before entering the pond. The species of Pelteobagrus fulvidraco are generally released in late April every year, and the matching silver carp should be released half a month after the fish has entered the pond to facilitate the growth of Pelteobagrus fulvidraco.

III. Key points of healthy feeding

1. Bait preparation. The food of Pelteobagrus fulvidraco in natural waters is mainly shrimp, fish and fish eggs and some aquatic insects, aquatic plants, so artificial culture can be raised with fresh animal bait.

The self-made compound bait is used for domestication and feeding, and the bait is made of fish meal, meat and bone meal, blood meal, soybean meal, rapeseed meal, dried fish and insect, etc. the protein content is more than 34% and the fat is 4%. In the later stage, small miscellaneous fish can be used to replace part of the fish meal, the protein content is 30% and the fat is 6%. Feed must be fresh, mildew-free and rancidity-free.

two。 Bait and domestication. Wild Pelteobagrus fulvidraco likes to eat at night and can be fed on the bait table during the day after domestication for 5 ~ 7 days under artificial culture conditions. Two days after the seedlings entered the pond, the seedlings were domesticated by artificial feeding, and the fixed feeding signal was used to carry out fixed-point and regular feeding training. After patient domestication for 5 ~ 7 days, the seedlings so domesticated can be fed normally on the second day after entering the pond, and the feeding method can be in the form of manual and mechanical feeding.

3. Amount of bait. The whole feeding process should be divided into three stages. In the first stage, bait was given four times a day in May and June, with a daily feeding rate of 3% to 5%. In the second stage, bait was given three times a day in July, August and September, with a feeding rate of 2% and 3%. In the third stage, the bait was used twice a day after October, with a feeding rate of 2%. On this basis, the feeding amount should be adjusted according to the weather and water quality, and the satiety method should be adopted in the first and third stages, that is, the feeding table. 90% of the fish stopped eating after leaving Taiwan. In the second stage, due to the hot weather and fluctuating water quality, it is recommended to feed "90% full", that is, 80% on the bait table, and stop feeding the fish after leaving the platform.

In addition, due to the large mouth crack of Pelteobagrus fulvidraco, the feed size should be increased correspondingly. With the particle size of 2 mm as the open feed, the particle size of adult fish can reach more than 5 mm. The use of sinking hard pellet feed requires that the particles should be stable for 15 minutes in water, and the use of floating bait will better improve the feed utilization rate.

Yellow croaker grows to 3 cm / tail, mainly feeding on aquatic organisms. If aquatic organisms are insufficient, pure dried silkworm pupa powder can be used instead. After 3 cm, eat artificial formula feed. Two or more feeding platforms suspended in the water can be set at the corner of the stocking pond, and the number of feeding platforms can be determined according to the size of the fishing pond and the number of fish released. The feeding table can be made of simple materials that can sink into water, and the table can be paved with soft materials such as woven bags. When feeding, knead powdered bait or pellets with water into small balls of two to three sizes, throw them on the stage and let the fish eat automatically. Feed each day once in the morning and once in the evening, and each time the bait should be fed as much as possible.

Fourth, water quality management is also key.

In the culture of adult yellow croaker, water quality management is the most important, and it is necessary to maintain a fresh water environment. In order to prevent the aging of the water body, 30 cm of new water is injected every month in May and June, and 15 cm is changed every half month from June to September, keeping the water depth at 1.2 m ~ 1.5 m. Insist on sprinkling l5ppm quicklime once a month from June to September in order to purify and disinfect water quality and reduce excessive organic suspended matter. Use 5kg quicklime (or 2kg bleach) locally in the food farm and aerator every semimonthly. Persist in observing the algal phase and algal concentration of the water body, adjust the water fertility with inorganic fertilizers (urea, calcium superphosphate, potassium dihydrogen phosphate, etc.) according to the water color, and keep the transparency at 30 cm ~ 35 cm. According to the determination of dissolved oxygen and the weather and water quality, the aerator should be used scientifically, the machine should be turned on in the early morning and afternoon in sunny days, and mechanical oxygen should be made full use of in rainy and muggy weather to supplement the lack of dissolved oxygen in water. Dissolved oxygen should be kept above 3 mg / L.

V. Drug selection depends on the curative effect.

Pelteobagrus fulvidraco has strong disease resistance and there is generally no major disease in culture, but yellow catfish is a scale-free fish, and its tolerance to commonly used drugs is not as good as that of the four major domestic fish. affected by season, air temperature, water quality, feeding and scale-free characteristics of fish body surface and bacteria and parasites in fishing ponds, it will also cause local infections and parasitic diseases, which need to be observed in peacetime culture and prevent in advance in view of abnormal conditions. In the prevention and treatment of diseases, high-efficiency and low-toxic drugs should be used as far as possible, and the varieties of drugs should be determined by observing the curative effect.

1. Insecticide. Sprinkle with the whole pool of 0.03ppm concentration per cubic body of water, or sprinkle with ketone sulfate than ferrous sulfate at a concentration ratio of 0.15 ∶ 0.05ppm. The above insecticides are better at killing insects such as ring worms and rotifers, but the two drugs can only be used alone, not mixed or used alternately, let alone overdose.

two。 Antibacterial and anti-inflammatory agents. Oral medicine (pressed granule mixed well in feed) mixed well with 10 grams of dysentery and 20 grams of oxytetracycline, added to 50 kilograms of bait, fed continuously for 3 days, twice a day, or oral penicillin capsule for 3 days, twice a day, the fish were disinfected with 0.25% bleaching powder or penicillin powder diluted and concentrated soaked for 10 minutes. The above oral ingredients, it is best to feed now, for three days at a time, do not put it for a long time. Mainly for diseased fish infected by bacteria.

3. The treatment of hemorrhagic disease. Sprinkle the whole pond with 50 kg of raw salt per mu. In order to cure the disease of yellow croaker, trichlorfon should be refused to kill insects, otherwise it will bring adverse consequences.

Try to avoid damage to fish during delivery and transportation, so as to prevent infection of water mildew in early spring, autumn and winter. If hemorrhagic edema occurs in the high temperature season, nitrogen dioxide should be sprinkled in the whole pool for 2 times, which can be treated effectively.