Cusk have an elongated body with a broad, flattened triangular head. The mouth is large and wide. A single chin barbel adorns the lower jaw. Scales are small and embedded giving burbot the appearance of being slimy. The anal and dorsal fins run nearly half the length of the body. Coloration ranges from a tan to dark brown background overlaid with dark brown to black mottling or spots. Some may be uniformly dark brown or black.