Tetradontidae (Tetradontidae; Puffer), commonly known as puffer fish, is a general term for the bream family fish. Fish is cylindrical, famous for its round body, generally about 100 ~ 300 mm long, up to 630mm or more. The maxilla, maxilla and tooth callus are combined into four large dental plates, and the body length can reach1.1m. Dorsal fin 1, no ventral fin. Scaleless or spiny. There is an airbag that can be inflated by inhalation. There are many kinds, most of which live in the sea, but they can also be found at the intersection of fresh water and sea fresh water. They blow up water and air in the water, make the sediment fly, and then prey on the creatures hidden in the sand. Because teeth and jaws are hard, even extremely hard shells can be crushed. It is oval, with a blunt front end and a tapered tail. The kiss is short, round and blunt; Small mouth, end position, transverse crack. There are two plate-shaped incisors in the upper and lower jaws, and the middle seam is obvious. The lips are developed, and both ends of the lower lip bend upward on the outer side of the upper lip. Small eyes, small gill holes, an arc crack, located in front of the pectoral fin, densely covered with small thorns. The dorsal fin is very backward, opposite to the gluteal fin; No ventral fins; The back end of the caudal fin is flat. The back of the body is grayish brown, the side is slightly yellowish brown, and the ventral surface is white; The marks on the back and side of the body vary from species to species.

Cuckoo is a kind of warm temperate and tropical offshore bottom fish, which lives in the middle and lower layers of the ocean. A few species enter the freshwater river, and when they encounter external danger, they float to the surface in a spherical shape, and at the same time, the small thorns on their skin stand up to defend themselves. Common ones are fugu rubripes, fugu rubripes, fugu obscurus, Portunus bipinnata, Chelidonium and Stichopus nigromaculatus.