Common Lumpsucker Identification Guide

Key identification features

• Rounded, almost globular body shape unlike any typical fish silhouette
• Rows of bony, wart-like tubercles running along the back and sides
• A sucker disc on the underside, formed from fused pelvic fins, used to grip rocks
• Small dorsal fin, often buried beneath a fleshy hump, especially in males
• Females grow much larger (to 50+ cm) and are grey-green; breeding males are smaller with blue-grey backs and orange-red bellies

Common look-alikes

• Leatherfin lumpsucker: smoother skin with far fewer and less pronounced tubercle rows
• Sea snail (Liparis species): soft, gelatinous, tadpole-shaped body lacking bony tubercles, with a much smaller sucker disc
• Grey seal pup mistaken visually at a distance: not a fish at all, but sometimes confused due to shape and color from afar

Where you'll see one

Common Lumpsuckers spend much of their life in open, cold North Atlantic waters, with juveniles drifting near the surface among floating seaweed. Adults move inshore to rocky, kelp-covered shallows to spawn, where males often guard the eggs.