Rock Gunnel Identification Guide
Recognize a Rock Gunnel by its slender, ribbon-like body and the row of dark spots along its dorsal fin base.
Read the full Rock Gunnel encyclopedia entry →Key identification features
- Slender, ribbon-like, eel-shaped body, flattened from side to side
- Long, continuous dorsal fin running nearly the full length of the back
- Olive-brown to yellowish-green coloring, sometimes with faint darker bars
- Row of small, dark, ringed spots (ocelli) along the base of the dorsal fin
- Small dark spot near the eye; grows to about 25-30 cm
Common look-alikes
- Shanny: stockier and blenny-shaped with a blunt head and large eyes, lacking the gunnel's row of dorsal ocelli
- Ocean pout: much thicker-bodied with plain mottled coloring and no dorsal spot row
- Sand eel: similarly slender but with a pointed, beak-like snout and no dorsal fin spots at all
Where you'll see one
Rock Gunnels live along rocky intertidal shores and tide pools on both sides of the North Atlantic, sheltering under rocks, in crevices, or among seaweed where they can survive brief exposure to air at low tide. Their slick, mucus-covered skin lets them wriggle easily between damp stones, and they are frequently the first fish found when turning over rocks near the low-tide line.
Frequently asked questions
How do I tell a Rock Gunnel from a Shanny?
Body shape is the giveaway: the Rock Gunnel is slender and ribbon-like with a row of dark spots along its dorsal fin base, while the Shanny is stockier with a blunt blenny-like head and no such spots.
Can a Rock Gunnel survive being found out of water at low tide?
Yes, it commonly shelters under damp rocks and seaweed during low tide and can tolerate brief air exposure, which is a useful behavioral clue when searching tide pools.