Graus nigra is a species of ray-finned fish endemic to the Pacific coast of South America, ranging from Valdivia in Chile to southern Peru.

), the Chilean sea urchin Loxechinus albus, and the labrid fish Galápagos sheephead (Semicossyphus darwini).

[6] Other carnivorous fish in the kelp forest include the Peruvian morwong (Cheilodactylus variegatus), the Chilean sandperch (Pinguipes chilensis) and the Cape redfish (Sebastes capensis); also present in this habitat is the herbivorous Aplodactylus punctatus.

[6] Graus nigra is a game fish, targeted by spear-fishers, both recreational fishermen and artisanal hunters.

These changes in abundance of some of the dominant carnivorous fish in the giant kelp forest has had a marked effect on the biodiversity of their habitats.