Six hundred wrasse species polish reefs in bright armour
Labridae holds over 600 marine species in 81 genera, many dazzlingly coloured. Most stay under 20 cm, yet humphead wrasse can reach 2.5 m. The English name comes from Cornish wragh for an old woman or hag. Parrotfish, once family Scaridae, often nest now as a wrasse subfamily or tribe.
Labridae is a sprawling family of more than 600 species in 81 genera and eight subfamilies, typically small fish, with the giant humphead a striking exception. The common name is Cornish in origin, where wragh meant a hag, kin to Welsh gwrach and Breton gwrac'h, while German and Dutch call them "lip-fishes" after their thick, sometimes folded lips. Parrotfish, once a family of their own, turn out to sit deep inside the wrasse tree and are now often treated as a subfamily or tribe. Fossils go back to the Early Eocene of Monte Bolca in Italy, and Middle Eocene remains from Antarctica show the family lived there until the continent cooled.
Their jaws are a biomechanics classic. Four rigid bones joined by movable hinges form a "four-bar linkage," which lets very different skull shapes produce the same result, whether fast protrusion or a hard bite, so unrelated lineages converge on the same job with different anatomy. Many species also smash clams, urchins and crabs against favoured rocks used as anvils; one blue tuskfish was filmed doing it to a young green turtle.
Sex is fluid. Most wrasses are protogynous hermaphrodites living in harems: juveniles mix both sexes, and the biggest adults become territorial males. When two male bluestreak cleaner wrasses share a tank, the smaller may revert to female, and a large female sometimes stays female when that pays off better. In the subfamily Labrinae, 15 of 23 species guard their eggs, with males building algae nests.
Cleaner wrasses run "stations" where larger fish queue to have parasites picked off, even from inside mouths and gills, though cleaners sometimes cheat by biting healthy tissue. In 2019 cleaner wrasses became the first fish to pass the mirror test, a claim the test's inventor Gordon Gallup disputes. People have long valued the family: the tautog was a staple for Indigenous peoples of the western Atlantic coast, and Scottish salmon farms now rear wrasses to eat sea lice.
Source: Wrasse
