Small and medium-sized marine fish. It has a long body and flat sides. Generally, it is 15 ~ 26 cm long and weighs 75 ~150 g. Its eyes are very small, and its front position and mouth are very cracked. The maxilla forms the upper edge of the oral fissure. The jaws are dense, thin and pointed, and the body is soft, most of them are smooth and scaleless, but there is a line of large scales extending to the tail fork on the side line. The head and back are light brown, the abdomen is milky white, and the lateral line is obviously developed, from the skull to the center of the caudal fork. There are 1 dorsal fin, only fins, no fin spines, and a small fat fin behind the dorsal fin; Thoracic fins and pottery fins are developed. About the same length; The caudal fin is trigeminal and the middle lobe is short.