Atlantic Halibut Identification Guide

Key identification features

• Very large, elongated diamond-shaped body, less rounded than most flatfish
• Both eyes on the right side of the head
• Lateral line arches gently upward above the pectoral fin, less curved than in Pacific halibut
• Dark olive-brown to nearly black upper side with subtle mottling; pure white underside
• Large mouth with sharp teeth, the jaw reaching back to below the eye
• Concave, slightly forked tail fin; can grow to 2-3 m and several hundred kilograms

Common look-alikes

• Pacific halibut – nearly identical in shape but geographically separate; its lateral line curve is even more subtle.
• Greenland halibut – smaller mouth, thinner body, and eyes set closer to the edge of the head.
• Common flatfish species (plaice, flounder) – all much smaller as adults and lack the halibut's massive jaw and size.

Where you'll see one

Atlantic halibut inhabit cold waters on both sides of the North Atlantic, ranging from continental shelves down to deep slopes between roughly 50 and 2,000 m. They favor sandy or gravelly bottoms and are typically solitary, bottom-dwelling fish found from the Gulf of Maine to the Barents Sea.