Nile tilapia

Nile tilapia (Oreochromisniloticus) is referred to as tilapia, also called Nile tilapia. It originated in Africa and was introduced in Taiwan Province of China in 1966. The effect of trial culture is good, and now it has become one of the main objects of freshwater culture in Taiwan. In 1978, this kind of fish was introduced successively from Thailand and Nile river systems in mainland China. The results of trial culture for many years show that Tilapia niloticus can adapt to the living conditions of water bodies in most parts of China, grow well and have a good effect on increasing production. At present, aquaculture has been promoted in more than 20 provinces, municipalities (autonomous regions) across the country. At the same time, there are Mozambican leek crucian carp (Oreochromismossambicus), Oriya tilapia crucian carp (O.aureus) and some other non-crucian carp.

The body of Nile tilapia is tall and flattened on the side, and the front of the head is slightly raised. The mouth is large, end position, upper and lower jaw denticulate teeth. The dorsal fin is quite long, with 16-17 hard spines in the anterior segment and 12-13 soft fins in the posterior segment. The body color is dark, the upper part is darker, and the lower part is lighter. There is a round black spot on the back of the dorsal fin. There are 8-10 faint black longitudinal stripes on the side of the body. There are obvious vertical stripes on the caudal fin. During the breeding period, the male fish has a bright body color, and its head, back and throat are red. The lateral line is discontinuous and is divided into upper and lower strips, the upper strip extends backward from the posterior upper edge of the operculum to the posterior end of the dorsal fin base, and the lower strip extends back to the caudal stalk from the center of the body near the pectoral fin.

Nile tilapia has a wide diet, mainly eating plankton in the juvenile stage, as well as organic detritus and small benthic invertebrates. And then. In addition to feeding on plankton, you can also eat a variety of plant leaves and buds. Under the condition of pond culture, they prefer to eat a variety of commercial feed, green feed and compound fish bait. Nile tilapia crucian carp has a wide diet, which is very beneficial to culture.

Nile tilapia lives in the middle and lower layers of the water body and often goes deep into the bottom to find food. It has a strong ability to tolerate hypoxia and can grow normally in water with only 2 mg / L of dissolved oxygen. But its cold resistance is very poor, so it is only suitable for living in water with a water temperature of 20-35 ℃. They stopped eating below 14 ℃, died one after another under 12 ℃, and it was difficult to survive when they were over 40 ℃. It has a certain salt tolerance and can be cultured in seawater with a salinity of less than 3%.

The breeding habit of Nile tilapia is very special. The first sexual maturity is only 4-5 months old. 5 Dan begins to lay eggs in the middle and late ten days of each year, and can lay eggs 4-6 times a year. During the reproductive period, male and female live in pairs. Males dig nests (spawning nests) in the sand with their mouths, and females lay eggs in the nests and then put the eggs into their mouths. The male fish standing next to the nest excretes semen at the same time. Sucked into the mouth of a female to fertilize the egg. The fertilized eggs hatch in the mouth of the female, and the larvae can be hatched after about 4 days when the water temperature is 28-29 ℃.

Nile tilapia crucian carp grows faster. After about 3 months of feeding, the body weight can reach 0.15-0.25 kg. It can be listed on the market. It has good meat quality and great edible value, so it is very popular among the masses.