This species exists in two distinctive phenotypes, with male individuals from West reef and Eccles reef possessing a bright yellow stripe of colour running from the tip of the snout over the anterior portion of the dorsal surface and along the distal margin of the dorsal fin. This form is commonly referred to as ‘sulphurhead’ or ‘sulfurhead’ in the aquarium hobby.

At Kande Island males exhibit a similar overall colour patterm but the dorsal stripe is whitish in colour and both males and females possess an enlarged lower pharyngeal bone. This population was described…