Medium-sized fish; maximum length of about 100 cm FL (fork length), but generally only about 60 cm. Metallic dark blue back, with intricate skew patterns ranging from mid-first back to back fin; the sides of the body and the silvery white belly, with distinctive dark patches between pectoral fins and abdominal fins, which are not always present. Without scales, except in the area of corselet and side lines.
Small teeth and conical, in a row. The filter comb is 29-34 in the first gill arch. The first dorsal fin with XI to XIV hard fingers (thorns), is separated from the second dorsal fin by only a narrow slit, which is narrower than the width of the eye. The spikes at the beginning of the first dorsal fin are much longer than the thorns behind them, making the top edges of the front fins curve deep. The pectoral fins are short, the edges do not reach the gap between the two dorsal fins. There are two bulges (flaps) between the two abdominal fins. Fins (finlet) 8-10 pieces behind the second dorsal fin, and 6-8 pieces behind the anal fin.
