Eel.

Monopterus albus belongs to Syngnathidae and Monopterus albus. Also known as eel, mackerel, eel, snake fish and long fish. About 15 species of slender eel-shaped fish.

Monopterus albus: It has no scales. It can erect its upper body in shallow water, breathe to the water surface through its mouth, and store air in its mouth and throat, so its throat is swollen. Freshwater edible fish, widely distributed in Southeast Asia, are produced everywhere except the northwest plateau, inhabiting ponds, rivers, rice fields and other places, often lurking in mud pits or crevices. Go out for food at night. The reproductive situation is quite special. She was a female when she was young, and after a reproduction, she became a male. This phenomenon is called sex reversal.