Call it the blue shark. Blue shark, also known as axe shark and tiger shark, belongs to catfish family. Origin in Thailand, Malaysia, the body length is about 8~ 15 CM, the body length of wild fish is 50CM, 1, body shape and body color. Freshwater sharks have four body colors: black, white, gray and red. Most of the sharks in the first three body colors are tropical fish. Blue sharks, especially gray sharks, have blue backs, blue-gray sides and silvery bellies. Red sharks, namely Crystal Badminton, are kept as ornamental fish [1]. 2. Adaptability and feeding habits. Freshwater sharks have strong tolerance to hypoxia and a wide range of adaptation, but weak tolerance to low temperature. The optimum temperature is 20℃-34℃, and the optimum growth water temperature is 26℃-32℃. When the water temperature is lower than 18℃, the activity is slow and the response is slow. Death began when the water temperature was lower than 65438 02℃. The food of this fish is mixed. Young fish feed on zooplankton, while adult fish feed on aquatic plants and artificial compound feed. Protein requirement of feed is 28%-32%. 3. Growth and reproduction. Freshwater sharks are omnivores, which eat a lot and grow fast. In that year, fry (3-4 cm) were cultured for 4 months, and their weight could reach more than 0.6 kg, and their sexual maturity was late. After feeding for 3-4 years, they could reproduce when their weight was more than 3 kg. The breeding season is from April to September, and it is a one-time spawning fish.