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.