Silk tail seedling cultivation technology

Mystus nunerus, also known as the white-bearded genus, is a genus of the genus Acrididae. In June 2000, the Institute of Fisheries Science and Technology of Baiyun District of Guangzhou City imported the first batch of silk-tailed seedlings from Malaysia. After careful observation of feeding, it was successfully tested and introduced.
First, biological characteristics
1?External form: head flat cone-shaped, trunk cylindrical, high back. There are barbs on the posterior edge of the dorsal fin spine, serrations on the anterior edge of the pectoral fin spine, and thick serrations on the posterior edge. There are fat fins, fin bases and anal fins. The caudal fin bifurcates and the upper lobe extends into a filamentous shape. There must be 4 pairs, including 1 pair of nose whiskers, 1 pair of upper jaws and 2 pairs of lower jaws. The upper jaw must be very long, and the ends of the upper fins should extend beyond the anal fins. The body is bare and scale-free with complete lateral lines. The body is gray, the abdomen is white, and there are no dark spots on the body surface and fins.
2? Habits: silk tail is a hot water fish, living temperature is 15 ~ 37 °C, the optimum temperature of 26 ~ 32 °C, significantly less than 15 °C discomfort, 14 °C fish lost balance. pH6.5-8.5, the requirement for dissolved oxygen in water is not high. Silk tail is a group of ground fishes with obvious cluster characteristics and easier catching. In Malaysia, silk tail is usually distributed in the estuary affected by tides, up to the shallow upstream waters, and also in the channels near the rice fields. Likes to inhabit in not very clear waters, water depth of 2 to 4 meters, no mud lakes or shore waters of the dam is its preferred habitat.
The fish is mainly omnivorous for animals. Under natural conditions, juveniles feed on plankton, and adult fish feed on larvae, small fish, crustaceans, aquatic insects, leeches, and organic debris. Under artificial conditions, various food feeds and their compound feeds can be ingested.
3. Growth and reproduction: The tail is faster and the individuals are larger. The seedlings can grow to 150 grams or more in the year, and 0.4 to 2.5 kilograms are common in natural waters. Females were 32.5 to 35.5 cm in size, and males began sexual maturity at 35.5 to 38.5 cm. In Malaysia, there are two major breeding seasons in the silk tail, the first phase is from February to April, and the second phase is from August to November.
Second, the breeding characteristics
1? Silk-tailed fry is easier to breed, with higher survival rate and faster speed. Normal fry can grow for 3 months to 4 centimeters in full length. Its complex food, feed easily resolved. However, if the water temperature is below 14°C, it will be cold and need to be preserved for winter.
2 silk layer likes cluster life, can be properly raised, but overstocking will affect the growth of fry. A better way to adjust the stocking density is to adopt a graded cultivation method. The first grade cultivation is from the seedlings to 4 to 5 cm, the stocking density is generally 300 to 500/m2, the second to 7 to 10 cm, and the stocking density is generally 80 to 120/m2.
3?Silk tail is Malaysia's famous fishing and eating fish, meat is delicate, taste cool, no intermuscula thorns, abdominal no black film, white flesh, no special smell of fish, loved deeply. In addition, the fish has the advantages of long speed, large individual size, mixed food habits, and high aquaculture production. It is a famous breeding new breed worthy of development.
Third, seed cultivation
1. Cultivation pond conditions: The newly introduced seedlings were cultivated in three fish ponds, of which J5 and J6 were cement cultivation ponds with an area of ​​6 square meters, a water depth of 45 centimeters, the water source was a stormwater tap water, and the young 5 was cement of an area of ​​60 square meters. Cultivation ponds, water depth of 60 cm, the source of water for underground wells. The second stage is cultivated in a 60 square meter concrete pool.
2. Seed stocking and harvesting: stocked rearing fish fry imported from Malaysia by air, the fry is of neat size and is about 2.5 cm in length. Due to some rotten tail disease, the fry is stocked with 10 mg/L furazolidone for soaking. .
3? Feeding management methods
(1) Feed Management: The silk tail fish fry with a total length of 2 to 3 cm can feed powdered formula feed, the first grade culture fish feed with squid, and the second grade culture feed powder with 40% crude protein. Straw feed, when mixed into a lump when feeding, every day in the morning and evening fed twice, feeding the amount of about 5% to 7% of body weight, and depending on food intake conditions adjusted.
(2) Water quality management: The water in the cement pool is small, the water quality is easily deteriorated, and micro-flowing water is generally added to the nursery. The remaining material and feces have great pollution to the water quality and should be promptly removed. Usually 2 to 3 days, the sewage is changed once, and the amount of water changed is about 50% of the original pool water to keep the water fresh. During the nursery period, it is inflated and oxygenated occasionally to keep the dissolved oxygen in the water adequate.
(3) Fish Disease Prevention: Silk tail has strong resistance to disease, but it may also be caused by stress factors such as deterioration of water quality, transportation, injury, severe oxygen deficiency, improper feeding, etc. Fish disease prevention and control is to avoid the above problems. The emergence of shocking factors. The fish diseases that emerged during the nursery period mainly included rotten tail disease and small melon worm disease. Bacteria caused by long-distance transport injuries can be treated with 0.5 mg/L furazolidone in pooled pool water and oral antibiotics. Scyllophagosis has a great impact on the survival rate of fry and should be promptly treated.