The most colourful of the British wrasses, it grows to about 35cm long and is found in the company of other wrasse species over rough weedy or rocky ground.
The male and the female are quite different in colouration but have the same body shape, they are a leaner fish than the Ballan or Corkwing and have a pointed face.
The colouration changes during the year, a breeding fish will have a different colour scheme to an immature non-breeding fish.
The male has the iridescent wavy lines that are seen on the male Corkwing and the Rock Cook but the lines are distinctly blue and not the blue/green of the
Corkwing; they extend right to the tail whereas the Corkwing shows mainly on the head and shoulders. The fringes of the fins are also distinctly coloured.
The Cuckoo Wrasse is less likely to be caught from the shore unless fishing into deep water, it will take most baits but ragworm can be counted on to catch.
Why it is called cuckoo is subject to speculation..... it shares no similarity with the bird but shares the sound of its name with the Rock Cook....which is also an odd name.
My suspicion is that there was an old dialect/Cornish/Breton/Welsh word that was pronounced cook but meant neither a bird or a chef, but something quite different.