Tiger sharks are native to rivers and lakes in Thailand, Malaysia and other countries. They are the main cultured fish in Southeast Asian countries, and they are also the favorite fishing objects. Tiger sharks have good meat quality, fast growth, large size, miscellaneous eating habits, hypoxia tolerance and easy fishing. Individuals who grow naturally for one year can reach1000g-2,000g-2,000g, and those who breed artificially can reach 3000g-5000g. It is a breeding variety with high economic value and development prospect.

I. Biological characteristics

Tiger sharks are divided into blue sharks and red sharks according to their body color. The body is long, the front is wide and fat, the back is slightly slender, the body surface is scaleless, and the head is round and blunt. There is a fat fin behind the dorsal fin and in front of the caudal stalk, and the caudal fin is deeply forked. Tiger sharks like to flock, inhabit the middle and lower layers of water, have a lively temperament and often float on the water. Its swim bladder is divided into a large number of saccular breathing chambers, which are important respiratory organs and can absorb oxygen in the air, which is more convenient for the survival and transportation of fish species and commercial fish. It has a strong tolerance to hypoxia, and tiger sharks can still live normally under the condition that carp fish in the same water body seriously float their heads. But its tolerance to low temperature is weak, and the suitable water temperature for its growth is 20℃-30℃. When the water temperature drops to 14℃- 18℃, its activity will decrease or even stop breathing. When the water temperature is 12℃- 13℃, it will cause shock or even death.

This kind of fish is omnivorous, and its main food is all kinds of rotting animal carcasses and plant debris in the water. Under the condition of artificial feeding, he likes to eat mixed feed made of fish meal, bean cake, bran, corn flour, wheat bran and other food scraps.

Second, adult fish culture.

After several years of introduction and breeding, tiger sharks have been successfully bred in Guangdong and Fujian in South China. Adult fish farming is still in its infancy. According to the experience of foreign culture, the culture of tiger sharks is similar to that of freshwater pomfret. The owner has two kinds of polyculture in Danyang River, which can be pond culture, or industrialized intensive culture and cage culture according to its advantages of fast growth and low oxygen consumption. It can be cultivated all the year round in places with hot springs and geothermal conditions.

Tiger sharks can be cultured in ponds with an area of 2000m2-3000m2 and a water depth of 1.5m-2m. Generally, 3 cm -4 cm long fish species are put, with 2000-3000 fish per mu. Every month, we mainly feed high protein concentrate such as rotifer, turtle feed and eel feed, and then feed artificial compound feed containing 27% crude protein. You can also use water hyacinth and cauliflower as pulp, and then mix it with crushed corn and bean dregs to feed. It can reach more than 750g in 3-4 months.

In polyculture, 100 tiger sharks can be polycultured in ponds where silver carp, grass carp and tilapia are raised, which will not affect the yield of main fish, but also increase the income of tiger sharks by 70 kg- 100 kg per mu.

Third, prevent and control fish diseases.

Rotten fin disease: the symptom is that the tail fin and dorsal fin of fish are congested and ulcerated. The cause is bacterial infection, and sick fish do not eat and die in large numbers, which is a serious infectious disease in the fry stage. The prevention method is to disinfect the pool water and use 15 mg/L formaldehyde, 10 mg/L potassium permanganate or 10-20 mg/L bleaching powder for medicinal bath. Antibiotics can also be added to the compound feed, and 30-40 oxytetracycline tablets per thousand fish species can be treated continuously for a week, so that the sick fish can be cured.

Cucurbitaceae diseases: It is easy to occur when the water temperature is 20℃-24℃. The symptoms are white spots on the body surface, pustules in severe cases, thin and wandering fish. The treatment method can spray 0. 1-0. 15 mg/L mercurous nitrate all over the pond, and repeat for 3-4 days, and the melon insects will automatically fall off.