Oplegnathus robinsoni, the Natal knifejaw, or also commonly known as Cuckoo Bass and Natalse Kraaibek, is a ray-finned fish that is endemic to the east coast of South Africa and Mozambique.

[5] A Natal knifejaws' diet includes ascidians (sea squirts), soft coral, and reef-encrusting organisms.

Now, the Natal knifejaw's habitat is only concentrated on the south coast of Africa and it suggests that their current distribution is largely affected by environmental factors.

The small area of distribution suggests that the Natal knifejaws did not adjust well to their environment after the LGM and only inhabit the southeast coast of Africa.

They are commonly found under floating objects at sea, while the larger juveniles occupy shallow subtidal reefs.

[2][3] There is fossil evidence showing that the family, Oplegnathidae, inhabited the northern part of Seymour Island in Antarctica.

[5] The beak-like shape of the Natal knifejaw's mouth makes them difficult to catch using a traditional rod and line.

Due to the damage induced by the spears and the large amount of specimens required for collection, data is lacking for the Natal knifejaw.