Rudderfish

Overview

The rudderfish (Centrolophus niger), also known as the black ruff, is a pelagic species and the sole member of its genus. It is widely distributed across temperate and subtropical waters in the Atlantic, Indian, and Pacific Oceans, as well as the Mediterranean Sea.

Distribution & habitat

This species is found in open-sea environments, typically ranging from epipelagic to bathypelagic zones. While adults generally inhabit deeper waters, often between 300 and 800 meters, juveniles are frequently observed near the surface, where they are known to associate with pelagic medusae and salps.

Appearance

The rudderfish has a robust, fusiform body that can reach significant lengths. Its coloration is typically dark brown to black, sometimes appearing with a bluish or purplish tint. The median and pelvic fins are notably darker than the rest of the body. Younger individuals are distinguished by the presence of two to four vertical bars along their sides.

Biology & behavior

This species is known to form small schools and is considered a hunter high in the food chain. While they may appear indifferent to divers, they remain cautious. Their diet is opportunistic, consisting of a variety of available prey including small fish, squid, and large pelagic crustaceans. Reproduction involves external fertilization, with the fish acting as open-water egg scatterers.