Tomcod Identification Guide

Key identification features

• Small, stocky, somewhat compressed body rarely exceeding 30 cm
• Olive-green to brown mottled back over a pale, silvery belly
• Small chin barbel
• Three dorsal fins and two anal fins, closely set together
• Rounded tail fin
• Large head relative to overall body size, with a blunt snout

Common look-alikes

• Juvenile Atlantic cod: grows much larger, with a more elongated body and stronger mottling than a mature tomcod
• Pacific tomcod: nearly identical in shape but found only in the Pacific, so range alone usually separates the two
• Rock gunnel: lacks a barbel and any dorsal fin division, showing a single long dorsal fin instead of three separate ones

Where you'll see one

Atlantic tomcod inhabits coastal and estuarine waters of the northwest Atlantic from Labrador south to the mid-Atlantic United States. It tolerates brackish and even fresh water better than most gadids, often entering rivers well upstream, and is notable for spawning in winter, sometimes right under river ice.