Leech, also known as water quality, belongs to leech family. Leeches mainly grow in inland fresh water. Its cylindrical shape is about 2 cm to 15 cm, which has extremely high medicinal value. Leech is also a traditional special medicinal aquatic animal in China.

Leeches generally grow in Song paddy fields and some diving ditches. Lao Huang likes to suck human and animal blood, and leeches are very agile. They can swim in the waves. Leeches will become very active when bloom is warm in spring. Every year from June to 10 is the spawning season of leeches, and Malaysia Airlines will be there in winter, but among you, you can't eat or move.

Leech belongs to cold-blooded annelids, which can grow and breed in the north and south of China. Moreover, leeches grow in lakes, reservoirs and paddy fields, and there will be more leeches in some polluted rivers or ponds rich in organic matter. The suitable temperature for leech growth is about 10~40℃.

There are about 500 species of leeches in the world, which are quite different from other annelids such as Nereis and Earthworms. Most horsetails are temporarily parasitic in vitro, while leeches have no bristles at the front and rear ends, so they have strong adsorption function and can assist in sports.

The sucker on the leech's head has anesthetic effect, and once it is attached to the surface of human body, it is difficult for human beings to detect it. When leeches bite animals or bite people, they suck people's or animals' skin with suction cups and then dive into the meat to suck blood. Moreover, leeches suck a lot of blood, generally 2 times to 10 times the weight of leeches, which is about 5 times the weight of leeches themselves. Leeches belong to hermaphroditic animals.