Shanny Identification Guide
Identify a Shanny by its stocky blenny body, blunt tentacle-free head, and mottled camouflage that shifts with its surroundings.
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Key identification features
- Stocky, blenny-shaped body with a blunt, rounded head
- Large eyes set high on the head
- Thick lips and a single long dorsal fin with a slight notch partway along
- No tentacles above the eyes, unlike many related blenny species
- Mottled olive-brown to grey camouflage pattern that can shift tone to match surroundings; typically under 16 cm
Common look-alikes
- Tompot blenny: has obvious branched tentacles above each eye and bolder striping, features the Shanny lacks
- Rock gunnel: much more elongated and ribbon-shaped, with a row of dark spots along the dorsal fin base and a pointed rather than blunt head
- Butterfish (blenny sense, in some regions): similarly slippery-skinned but more slender-bodied without the Shanny's blunt head profile
Where you'll see one
Shannies are among the most common fish found in rocky intertidal pools and under seaweed-covered stones along the northeast Atlantic coast, from Norway to Morocco, tolerating brief exposure to air at low tide. Their ability to survive out of water for short periods makes them a familiar find for anyone turning over rocks or checking pools during a falling tide.
Frequently asked questions
How do I tell a Shanny from a Tompot Blenny?
Check above the eyes: a Tompot Blenny has obvious branched tentacles there, while a Shanny's head is completely smooth and blunt with no tentacles.
Why do Shannies seem to change color between rock pools?
Their mottled pigment can shift tone to better match the surrounding rock and seaweed, which is a normal camouflage response rather than a sign of a different species.