The body is elongated, flat or slightly flat at the back. The head is quite flat and covered with mucro or ridges. Big eyes, upper side position. Mouth end position; Maxillary, mandible, hoe and palate: the bone has fluffy teeth, and sometimes the teeth are large and canine-shaped. Gill rakes are short and few. The body is covered with comb scales; The lateral line is complete. No swim. There are two dorsal fins, the first dorsal fin is hard spines with VI-X; The second dorsal fin flexible strip 11-15; Gluteal fin soft strips 11-14; The ventral fin is located behind the base of pectoral fin. There are about 18 genera and 6 species in the world (Nelson, 1994).

mackerel, commonly known as oxtail fish, is commonly called "flatheads" in English, which is a small group of squids with flat heads. Similar to Cetaceae, the head is usually spiny or serrated. Oxtail fish has a long body, a flat head, eyes protruding above, a big mouth and a protruding jaw, and a huge mouth can swallow a lot of prey. It is a typical hunter. It belongs to benthic fish and feeds on small rolls, crabs, shrimps and small fish. The orbital oxtail fish is a kind of edible fish which is large in size and can often be seen in the fishing market. It is covered with dark brown spots and has eight obvious dark straight spots on its back.