The Gladius sea chub (Kyphosus gladius) is a species of marine ray-finned fish, a sea chub in the family Kyphosidae. It was recognised a new species in 2013 and is found in the southeastern Indian Ocean where endemic to the southern coasts of Western Australia. The distribution runs from the Houtman Abrolhos to Albany. Kyphosus gladius has an elongated, elliptically-shaped body with a terminal mouth and a short head. There are 55-64 scales in the lateral line of which 44-55 are pored. The caudal peduncle is long and shallow. Most of the head and body is covered in large, ctenoid scales. The continuous dorsal fin has 10 - 11 spines and 11-12 soft rays and the short-based anal fin has 3 spines and 11-12 soft rays. The overall colour is silvery to metallic bluish, the gill cover has a vertical green bar near its rear and the back is darker than the underparts, although this is not seen as counter-shading. The standard length of the largest fish measured is 45.7 centimetres (18.0 in).
