The maximum length of the blue-patterned hanger is 25cm. The body of the blue-striped fish is oval and flat on the side. The head is small, the outline of the back of the head is obviously protruding, the more obvious it is in the adult fish. The mouth is small, end position, with a row of flat teeth in the upper and lower jaws, the teeth are fixed and immovable, and the tooth margins are notched. The spines of the dorsal and anal fins are sharp, and the rays are not extended; the pectoral fins are nearly triangular; the soft rays of the dorsal and anal fins are angular; the caudal fin is crescent-shaped, and the upper and lower lobes gradually lengthen as they grow.

The blue stripe hangs into a purple-grey fish, and the sides are densely covered with light blue wavy horizontal lines The pelvic, anal, and caudal fins are purple-black; the pectoral and dorsal fins are creamy yellow, and the end of the dorsal fin and tail spine are purple. The main difference between juveniles and adults is body color. Juveniles are uniformly brown, with light blue wavy stripes on the sides and light blue diagonal stripes on the head. The pelvic, dorsal, anal and caudal fins are dark brown with blue borders.