Small eel-like fish. Distinguished by a row of ocellated (eye) spots
(9 - 15) underneath the long dorsal fin that runs the length of its body.
Orange-brown. Ocellated spots often not clearly visible in small specimens.
Similar species: Common Eel Anguilla,
and Eelpout Zoarces viviparus.
Breeding: Winter - spring.
Eggs guarded by the male fish, intertidally (north) to 25 metres depth.
Habitat: Benthic, shallow seas,
intertidal except summer.
Worms, small crustaceans like amphipods.
Adults probably eat the Hermit Crab commensal
ragworm Nereis fucata. (pic)
It was really fascinating to watch the small
South-clawed Hermit Crab, Diogenes pugilator, moulting
inside its shell. Alas the predatory Butterfish, Pholis gunnellus,
was much too quick and it had the soft-shelled hermit crab for dinner in
a fraction of a second. The Boar Fish, Capros aper,
paid little heed.
Butterfish show an predatory interest in the
activities of hermit crabs, including the Common Hermit Crab, Pagurus
bernhardus, with the ragworm Nereis fucata residing
All British coasts. Common in the north and only occasionally found
intertidally in the extreme south-west. Very common off some Scottish coasts.
Atlantic coast of North America.
Sussex: frequent in spring and autumn intertidally on rocky shores.
Rarely in large pools (On Sussex shores, 1 in a 1000+ only).
Northern fish so unable to tolerate living on the shore during the
summer, where it is common under stones in the spring and autumn. Often
infected with the Black-spot disease Cryptocotyle
Eaten by otters off Scottish coast. Mucus covered scale-less body is
very slippery, hence its common name. Impossible to grab hold of by the
gunnellus, infected with the Black-spot parasite Cryptocotyle lingua.
style of the trigenetic parasite Cryptocotyle lingua.
Observations and Discussion (Marine Wildlife of the North-east Atlantic
A very red Butterfish (photograph
photographs of Butterfish
Some books misidentify this fish as the Eelpout Zoarces viviparus.
The scientific species name gunnellus probably came from the
word "gunwhale" or "gunwale" pronounced
Butterfish located in Loch Creran, Argyll, Scotland. (56° 31' N, 5°
Prevalent. Identified using various
text and advice of a senior lecturer. Peter
R Haylock, Heriot-Watt University.
April 2000: under Selsey Lifeboat Station,
West Sussex coast (Paul Parsons). Clay bedrock with
Frequently discovered at Kingston
Beach, Shoreham-by-Sea, spring and autumn. Rarely (1 in a 1000) in
30 September 2000:
Someone brought in a small Butterfish, Pholis
gunnellus, found in a crab trap in the River Exe. Jenny Nunn, (Axmouth
Sea Discovery Centre)
>Hi Andy........Pholis gunnellus are rare
in Swansea and Gower.....the odd one found maybe in spring...in Pembrokeshire
they are quite common in Spring and rarely found in summer, but always
under stones everywhere, often with young river Eels..........never in
pools. Jim Hall
Neil Watkins discovered
these fish on Auchmithie beach in Angus, Scotland. They range in
size from about 6 cm to approx 15 cm.
I did research on this fish back in 1969, at
the Marine Lab on Hayling Island. Fish were numerous in Langstone Harbour,
Hants. I have also regularly found them on the stony beach at Lyme Regis,
where I ran a field studies course for many years, still present in 1999.
Also present just offshore at low tide from Charmouth to West Bay, Dorset.
Determining factor certainly seems to be substrate. I rarely found them
in conditions that tended towards anaerobic, ie, mud or muddy sand. Most
commonly they were below MTL, and I have discovered them most months of
the year, certainly in the summer months. Martin
I saw a Butterfish while diving under Trefor
Pier (Snowdon, Wales) Sunday 27th May
2001. Gianfranco Unali
I spotted several Butterfish at St Abbs (shore
dive heading for Cathedral rock), SE Scotland on the 21st
Sept 2002. Simon
March or April 2003
I had a sighting of a Butterfish whilst scuba diving on a wreck
in Scapa flow in the Orkney Islands in October 2002.
I thought I should write to report the capture
of a butterfish in the Holes bay area of Poole harbour, Dorset. A friend
,while netting prawns along the quay wall, caught this very attractive
small eel. After identifying it from a book, he brought it to me for my
marine aquarium where it is now residing together with a wrasse and some
blennies. During the search for more information on this species I came
across your website.
6 August 2003
Me and my Dad found a butterfish in a rock pool in Gardenstown Beach
in the Moray Firth, Scotland. At first we thought it was a baby moray eel
when we studied it in the net we had caught it in, but later identified
it as a Butterfish once we referred to your website.
For some time now (the past three years) I have been occasionally
spotting this uncommon eel where I work. I usually find it inside of clusters
of seaweed I have to pull out of the water. I have taken photos of it in
order to show it around to try and have someone identify it for me. To
no avail. Then, just by sheer accident, I saw it's picture on your website.
It's a Rock Gunnel. Finally, mystery
solved. Thank you.
/ Club Steward, Ipswich Bay Yacht Club, Ipswich, Massachusetts, U.S.A.
Information wanted: Please send any records of this fish, with
location, date, who discovered it, how it was identified, prevalence, common
name and any other details to
All messages will receive a reply.