The Cape knifejaw is a dark, oval-shaped fish that can grow to almost a metre in length. Its colouration is generally a dark grey, with a lighter-coloured mouth and underparts.
The juvenile Cape knifejaw is bright yellow, with black, vertical bands over its eye and in front of its tail.
The knifejaw’s teeth are fused to form a beak-like structure. It is an omnivore and feeds on a variety of food sources around near-shore reefs. Its beak is used to break up sea squirts, sponges and red algae. The Cape knifejaw becomes territorial when it matures and forms a pair that hunts together.
The Cape knifejaw is endemic to South Africa, ranging from False Bay to Thukela.
The Cape knifejaw is on the SASSI Red list.