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.

Kyphosus gladius has an elongated, elliptically-shaped body with a terminal mouth and a short head.

[1] 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.

[1] Kyphosus gladius is found in the southeastern Indian Ocean where it is endemic to the southern coasts of Western Australia.

[2] Kyphosus gladius was described in 2013 by Steen Wilhelm Knudsen and Kendall D. Clements with the type locality given as Canal Rocks, Yallingup Reef, Western Australia.