It is not the same kind of fish. It is often said that saury is not a marine fish, but hairtail is a marine fish. Hairtail is also often called saury.

Coilia ectenes Jordan, also known as Coilia ectenes, is a migratory fish, which is also known as Coilia ectenes Jordan, along with puffer fish and shad, and is one of the three fresh fish in the Yangtze River in China.

Hairtail [1] belongs to trichiuridae, a perciformes of bony fishes in the subphylum Vertebrates of Chordata. Also known as saury, nepotism, fat belt, oil belt, toothfish, etc., it is fierce. Hairtail is flat as a ribbon, silvery gray, with light gray dorsal fin and pectoral fin, with tiny spots, black tail, big mouth of hairtail, and gradually tapering to the tail, and its height is twice as long as the head, and its total length is about 1 m.. It is fierce and mainly feeds on shrimps and squid. It is mainly distributed in the western Pacific Ocean and Indian Ocean, and distributed in the Yellow Sea, East China Sea, Bohai Sea and South China Sea in China. It is also known as the four major seafood in China with large yellow croaker, small yellow croaker and squid.