The technology of intensive culture of black fish

Ophiocephalus argus commonly known as black fish, grouper, garrhead fish and so on. At present, the main species cultivated in China are snakehead, snakehead and their hybrids. Ophiocephalus argus is a kind of valuable economic fish with large individual size, fast growth, high yield and economic value. Its meat is delicate, delicious, less thorn and more meat, fast growth and high nutritional value. In addition, snakehead has strong adaptability, rapid growth and convenient transportation. In recent years, with the development of domestic aquaculture and the needs of foreign trade, snakehead has gradually become a special breed of production and marketing, and is welcomed by the majority of farmers.

1. Pond conditions Pond selection in sufficient water, neutral or slightly alkaline water quality, fresh water quality, pollution-free reservoir side; pool rectangular, drainage, irrigation convenience, an area of 2000 square meters, water depth in an average of 1.2 meters above, the deepest up to 2 meters, the bottom of the pool to stay 10 cm thick sludge.

2. Preparatory work ① before stocking drained pool water, the whole pool solid slope, remove excessive silt, let the pond freeze, sun for a period of time. 10 days before stocking, 667 square meters were disinfected by spraying 100 kg quicklime. Add fresh water after 5 days. (2) In late April, aquatic plants such as water hyacinth are planted in shallow water around the pond. The coverage area of aquatic plants after growth shall not exceed 25% of the total area of water body, so as to provide shelter for snakehead, and it is beneficial to improve water quality and reduce water temperature in high temperature season. (3) snakehead is lively by nature. Bamboo fence and nylon net are used to surround the pond more than 50 cm high to prevent fish from jumping out of the pond.

3. Seed selection and release ① Species selection. selecting seedlings with consistent specifications, smooth body surface, plump muscles, no injury or disease, active swimming and fierce competition for food. (2) stocking time and specifications. There are two kinds of fish species in pond culture: one is the large-sized fish species with more than 50 grams per tail, which should be stocked into the pond in early winter; the other is the small-sized fish species with 60 ~200 fish per kilogram, which is bred from the early spring seedlings of the year after about 2 months, and should be stocked into the pond in June ~ July.③ stocking density. 4000 ~5000 fish species are stocked per 667 square meters.

4. Channa argus is a carnivorous fish fed with feed. At present, most of the artificial culture of snakehead feeding fish, shrimp, snails, mussels and other fresh bait. When feeding fresh bait manually, pay attention to freshness and cleanliness, and soak it in 6%~8% saline for 10 minutes ~15 minutes before feeding; the feeding amount is 6%~8% of the fish weight. Feed regularly and quantitatively two or three times a day. If the fish and shrimp are insufficient, they can also be fed with other animal waste (such as livestock and poultry internal organs). The waste should be fresh and clean. When feeding, it should be chopped up and disinfected. Artificial synthetic bait can also be prepared according to the nutritional needs of Ophiocephalus argus to supplement the shortage of fresh bait.

5. Water quality management High-density culture, due to residual bait, excreta more, water quality easy to turn black, smelly, affect the healthy growth and quality of snakehead, but also cause disease, must take comprehensive measures to control water quality: first, frequent water change, breeding early and late, every 5 days to 7 days to change the water once, July to September every 4 days to change the water once, each time 30 cm deep. The second is the use of biological agents, such as regular use of photosynthetic bacteria, phagocytosis of harmful bacteria. Third, timely open the aerator, oxygenation, aeration, promote the decomposition of harmful substances such as hydrogen sulfide and ammonia nitrogen at the bottom of the pool, and keep the transparency of the pool water above 35 cm.

6. Disease control and prevention of snakehead disease should adhere to the principle of "prevention first," in the whole breeding period, regular disinfection of water. Disinfect the fish pond once after 1 month and once every half month thereafter. Disinfectant drugs include: dibromohydantoin, chlorine dioxide, quicklime, bleaching powder, etc., the amount according to the water quality and drug use instructions. Vitamin C, allicin and Sanhuang powder are added regularly in the bait, which is beneficial to enhance the physique and disease resistance of Ophiocephalus argus. Pay more attention to observation during breeding period, and take effective measures to prevent and control epidemic situation in time.