Cold-water resident of the subantarctic reefs. This fish carries antifreeze. It lives among the kelp forests and rocky crevices of the remote southern islands. Its body produces natural antifreeze proteins that prevent ice crystals from forming in its blood. This remarkable adaptation allows it to thrive in waters that would kill other fish. A fish that does not freeze. The biology is specific. The survival is absolute. The body is robust and muscular, with a large head and a terminal mouth. The colour is a dark brown or black, providing camouflage against the dark rocks and kelp. The fins are rounded and strong. The scales are small and embedded in thick skin. It is a fish of the cold, adapted to water temperatures near freezing. The texture is rough. The appearance is sombre. Antifreeze proteins circulate in its blood and tissues, binding to small ice crystals and preventing them from growing. This adaptation has evolved independently in several groups of Antarctic and subantarctic fish. It allows them to survive in water that would freeze the blood of any other fish. The chemistry is precise. The margin for error is zero. It acts as a sit-and-wait predator, hiding in crevices and ambushing prey that swims too close. It eats small fish, crustaceans and worms. It is most active at dawn and dusk, when the light is low and the prey is most vulnerable. The strategy relies on patience. Speed is secondary. The ambush is sudden. It is not targeted by commercial fisheries in New Zealand waters. The subantarctic islands are remote, and fishing is limited. The main threat is climate change. As the oceans warm, the cold water that this fish depends on will shrink. It has nowhere to go. It is at the southern edge of the world. The retreat is impossible. The habitat is finite. The subantarctic water is cold. The black cod hides among the kelp, dark and still, antifreeze proteins in its blood. The water is warming. The cod does not know. It just wants to eat a crab. The ghosts of the southern reefs are adapted to a world of ice and cold. The black cod is proof. For now. The future is uncertain.