Eels have special habits. They have migratory habits, but unlike most migratory fish, eels reproduce in seawater, and after they lay eggs, they will enter fresh water. Therefore, most eels live in the waters where fresh water and salt water meet.

Most eels in the world live in temperate and tropical regions, most eels live in the Indian Ocean and Pacific Ocean, and only a few European eels and American eels live in the Atlantic Ocean. There are also some eel species in China, mainly distributed in Yangtze River, Minjiang River, Pearl River, Hainan Island and other regions. There are many species of eel, and the habits and distribution range of different species of eel are also different.

Eels like to inhabit clean and refreshing waters. They have migratory habits, but they are different from other migratory fish. They will grow in fresh water and migrate to sea water to lay eggs as adults. Their migration mode is called downriver migration. Eels lay eggs only once in their life, and they die after laying eggs.

The sex of eel birth is also quite special. Their sex is determined by the environment. When the number of their population is small, the proportion of female fish will be higher. When the population is large, the number of female fish will decrease. Because eels have special migratory habits, it is difficult to cultivate them artificially.