Freshwater sharks are also known as Pangasius, Fishhead, Tigerhead, Paddy, or Bajin fish, and are mainly distributed in Southeast Asia. They are newly introduced freshwater varieties. First, biological characteristics 1. Body type and body color. Freshwater shark body color is black, white, gray, red four. The sharks of the first three colors are mostly kept as food fish, and grey sharks are the most popular. Their back is blue, blue on the side of the body, and silvery white on the abdomen; red sharks are crystal puddles and are mostly kept as ornamental fish. 2. Adaptability and food habits. Freshwater sharks are resistant to hypoxia and have wide adaptability, but they have low resistance to low temperature. The optimum temperature is 20-34°C, and the optimum growth temperature is 26-32°C. When the water temperature is lower than 18°C, the activity is slow, and it is slow to reflect; when the water temperature is lower than 12°C, it begins to die. The fish has a more complex diet. Juveniles use zooplankton as bait. Adult fish feed on aquatic plants and artificial compound feeds. Forage protein requires 28% to 32%. 3. Growth and reproduction. Freshwater sharks have mixed food, large food intake, and fast growth. When the fry (3-4cm) was reared for 4 months, the body weight was more than 0.6kg. The fish is more mature and can breed for 3 to 4 years and a body weight of more than 3kg. The breeding season is April-September and it is a one-time spawning fish. Second, aquaculture technology 1. Single pond. The pond area can be 1-10 mu, water depth is 1.2-2m; in April and May every year, when the water temperature is stable above 18°C, the seed size of 5cm-10cm can be stocked, and the stocking capacity per acre is generally From 1000 to 2000 fish ponds with better conditions can stock 2000 to 3000 tails; they are fed with artificial pellet feed and fed twice a day, and the feeding amount is 3 to 5% of the fish's body weight. 2. Pond polyculture. It can be mixed with all home fish, tilapia, spots and tails, shrimps, crabs, etc. Generally, the amount of polyculture on the water surface per mu is 100-200 tails (size 5-10cm), and no additional feeding is required. 3. Cage culture. The cage size is generally 4mX4Mx2m or 5Mx5mX2m. The effective breeding water body is 25 to 45 cubic meters, and the stocking size is 8cm to 10cm fish species 100-150 tail/m3. Feed artificially formulated feed pellets, feed protein requirements 28% -32%, preferably floating aquatic feed. Third, feeding and management 1. Feed and feed. Newly hatched fish fry use aquatic animals and plants as baits, which can be cultivated by means of rearing four fry fish fry. If the cement tank is used for cultivation, it can be fed with leeches or squid feed. When the larvae grow to more than 5cm, they can be fed nutritious pellet feed or crushed material. Adult fish breeding mainly feed pelleted feed. The grain size of the pellets fed at each stage should be compatible with the caliber of the fish. They should be fed twice or three times per day, and the daily feeding amount should be 3%-5% of the body weight of the fish. When feeding feed, you should do "three look" and "four set". 2. Diseases and prevention. The practice of breeding shows that freshwater sharks are more sensitive to chemical drugs. Therefore, chemical drugs with strong irritating effects and large side effects should be avoided during feeding. In the epidemic season of fish disease, regular spillage of “chlorine†drugs or addition of “Allicin†and “Oxytetracycline†to feeds will prevent the occurrence of bacterial or viral diseases. In the fry stage, it is easy to infect parasitic diseases such as small melons and trichotomous worms. If suffering from skin diseases such as skin skin, acne and Other skin diseases, 20 ppm formalin can be used to splash the whole body and maintain the efficacy for more than 2 hours.
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