Wrasse
A large family of colourful marine fish known for sex change and cleaning symbiosis.
Wrasses are a diverse group of ray-finned fish in the family Labridae, comprising over 600 species. They inhabit tropical and temperate waters worldwide, playing key roles in reef ecosystems through predation, tool use, and cleaning services for other fish.
- Over 600 species exist in the family Labridae.
- Humphead wrasses grow up to 2.5 metres long.
- Many species change sex from female to male.
- Cleaner wrasses remove parasites from other fish.
- Some species use rocks as anvils to smash shells.
What it is
The wrasses form the family Labridae, a vast group of marine ray-finned fish containing more than six hundred species across eighty-one genera. Most individuals are small, measuring under twenty centimetres, though the humphead wrasse reaches two and a half metres. These fish display bright colours and possess protractile mouths with distinct teeth. Their dorsal fins typically span most of their backs, featuring between eight and twenty-one spines. Many species exhibit sexual dimorphism, with juveniles appearing as mixed males and females before some mature into terminal-phase males.
Where it lives
These fish occupy tropical and subtropical zones across the Atlantic, Indian, and Pacific Oceans. Certain species tolerate cooler conditions, such as the Ballan wrasse found near Norway. They prefer shallow environments like coral reefs and rocky coastlines, staying close to the sea floor. Fossil evidence indicates they once ranged widely, including Antarctica during the Eocene epoch, before cooling climates eliminated them from polar regions.
How it lives
Wrasses are efficient carnivores that consume various small invertebrates. Smaller species often follow larger fish to catch disturbed prey. Some juveniles hide within mushroom coral tentacles. They serve as primary models for studying fish-feeding biomechanics due to their unique four-bar linkage jaw structure, which decouples form from function. This anatomy allows for rapid protrusion or powerful biting depending on the ecological need.
Breeding and life cycle
Most labrids are protogynous hermaphrodites, meaning they start as females and become males. Mating systems include polygynous, lek-like, and promiscuous arrangements. While many release planktonic eggs into currents, the subfamily Labrinae exhibits parental care, with males building nests and defending eggs. Sex change is usually female-to-male, though experimental conditions can reverse this process.
Fish and people
Indigenous peoples in Western North America historically consumed tautog, a wrasse species. Today, many wrasses populate public and home aquaria, with some considered safe for reef tanks. In Scotland, cleaner wrasses are farmed to control sea lice in salmon farms. The bluestreak cleaner wrasse is notable for its role in cleaning symbiosis, removing parasites from client fish at designated stations.
Questions people ask about Wrasse
What makes wrasse jaws unique?
Their jaws feature a four-bar linkage system where rigid bones connect via moving joints. This design allows different physical shapes to achieve identical mechanical results, such as fast biting or forceful crushing, adapting morphology to specific ecological niches.
Do all wrasses change sex?
No. Some species exhibit functional gonochorism, remaining male or female throughout life. Others are protogynous, starting as females and becoming males. A few lineages allow individuals born as either sex to potentially switch roles later in life.
How do cleaner wrasses interact with clients?
They live in symbiosis with larger fish, grooming them by eating parasites, dead tissue, and mucus. Client fish gather at cleaning stations, allowing cleaners to enter mouths and gills. Occasionally, cleaners cheat by eating healthy tissue.
Are wrasses capable of using tools?
Yes. At least twenty-one species use hard objects like rocks or coral as anvils to smash open shelled prey such as clams and crabs. Some individuals remember specific locations to reuse these tools repeatedly.
Good reading and sources
The facts on this page come from the Wikipedia article "Wrasse", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
Like Wrasse
All reef fish
WorldSeahorse
Small marine fish with horse-like heads and curled tails in the genus Hippocampus.Other · Coasts and shelves
WorldParrotfish
Reef-dwelling wrasses with beak-like teeth that grind coral into sand.Reef fish · Coasts and shelves
WorldBluespotted cornetfish
Long, slender reef fish with a tubular snout and blue spots.Reef fish · Coasts and shelves
WorldDamselfish
Small marine fish known for aggressive territorial behaviour and reef farming.Reef fish · Coasts and shelves