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March 5, 2025
This week’s Species in Focus is the Cornish Sucker. This unique looking fish may be little but packs a powerful ability to latch on to rocky surfaces using its adapted pelvic fins.
A small fish with a rounded snout and a dorsoventrally flattened body less than 7cm in length. The Cornish sucker is a cryptobenthic species, meaning it is camouflaged to its environment both by its appearance and by its behaviour. The body of the fish ranges from deep reddish purple in colour to a lighter brown/green, with dark, circular markings and a pair of electric blue eyespots behind the head. The pelvic fins of clingfish are specially adapted to form a sucking disc, creating a tight seal between the body and the rock surface and preventing them from being dislodged by wave action in the intertidal zone.
The species name is Lepadogaster purpurea.
Often found clinging to the smooth surfaces of boulders and large rocks on the lower shore, as well as tucked under weed-covered crevices. Individuals may be seen to be closely guarding amber-coloured clusters of eggs on the underside of larger rocks.
The Cornish sucker is a detritivore, feeding on the decomposing organic material of its environment.
The Cornish sucker has been found during Bioblitz surveys by our members, particularly during our Bespoke Rockpool Discovery sessions, and has been recorded at eight of our sites across Cornwall.
