Cleaner Wrasse

SizeUnknown

LifespanUp to 4 years

StatusNot Evaluated

About

Cleaner Wrasse

The bluestreak cleaner wrasse (Labroides dimidiatus), also known as the blue diesel wrasse, is a slender reef fish renowned for its vital mutualistic role on coral reefs. Adults feature a pale yellowish to bluish-grey anterior body that transitions into a vivid electric blue towards the posterior. A distinct longitudinal black stripe runs along the side of the body from the snout through the eye, widening as it reaches the tail fin. Adults reach an average length of 10 cm and a maximum size of 14 cm. Juveniles display a contrasting appearance, featuring a dark black body marked by a single bright electric-blue line running along the upper side. This species establishes defined cleaning stations at prominent coral heads across shallow and subtidal reefs. Operating singly, in pairs, or in social groups, cleaner wrasses attract client fish by performing a characteristic dance, moving their tail up and down in the water. Client fish recognise the wrasse by its side stripe and swimming pattern, responding by adopting stationary, species-specific poses. They spread their fins and open their mouths and gill covers, allowing the wrasse to enter safely and pick off ectoparasites, dead tissue, and excess mucus. To keep client fish calm and immobile during cleaning, the wrasse rapidly beats its pelvic fins against the client's body, providing a soothing tactile sensation. This service benefits both parties: the wrasse obtains a steady food supply and immunity from predation, while clients enjoy reduced parasite loads, lower infection rates, and improved body condition. The wrasse interacts with a vast range of clients, including surgeonfish, moray eels, bullseyes, sharks, sea turtles, lobsters, and octopuses. Cleaner wrasses live in social groups known as harems, comprising a dominant male and several females. All individuals are born female; if the dominant male dies, the largest female changes sex to become a functional male and takes control of the territory. At night, they retreat into small reef crevices, occasionally secreting a cocoon of protective mucus. Divers highly prize encounters at cleaning stations, where they can watch diverse marine life queue patiently while remaining vigilant for the sabretoothed blenny, a mimic that copies the cleaner's pattern to nip flesh from unsuspecting fish.

Size

Unknown

Weight

5-15 g

Lifespan

Up to 4 years

Status

Not Evaluated

Where to Find Them

Best Diving Locations

Diving Tips

Locating cleaner wrasses is straightforward for scuba divers, as they maintain fixed cleaning stations around prominent coral formations, shallow reef flats, and seaward slopes. To observe cleaning interactions without causing disruption, divers should approach the station slowly, maintain neutral buoyancy, and settle at a respectful distance. Avoid getting too close to the coral structure, as sudden movements or heavy bubble exhaust can startle client fish and cause them to break their stationary poses or abandon the queue. Observe the wrasse's distinctive greeting behaviour, where it moves its tail up and down in a dance-like motion to attract visitors. Look closely at how client fish—ranging from small damselfish to giant moray eels—hold still with spread fins or gaping mouths to permit access to their gills and teeth. Divers should also watch for the rapid flutter of the wrasse's pelvic fins against the client's skin, which acts as a tactile massage to keep the client stationary. Finally, take time to inspect cleaner wrasses closely: watch out for the false cleaner wrasse (sabretoothed blenny, *Aspidontus taeniatus*), which mimics the cleaner wrasse's stripe and dance but possesses sharp fangs used to bite flesh from trusting fish rather than clean them.

Best Season

The bluestreak cleaner wrasse is a resident, non-migratory reef fish found year-round across its extensive range in the tropical and temperate Indo-Pacific. Because these wrasses occupy permanent cleaning stations on shallow coral reef flats and seaward slopes, diver encounters are consistent in every season, provided local water conditions and sea state permit reef diving. In tropical regions such as the Red Sea, East Africa, the Persian Gulf, French Polynesia, Fiji, and Papua New Guinea, water temperatures remain warm throughout the year, ensuring reliable daily cleaning station activity. In temperate margins of its range, including southern Japan, the southern Great Barrier Reef, southwestern Australia, and the Kermadec Islands Marine Reserve north of New Zealand, encounters depend primarily on seasonal dive weather and sea conditions rather than fluctuations in the fish population. Because cleaner wrasses rely on client parasites, mucus, and corals for daily sustenance, cleaning stations remain active continuously during daylight hours across all twelve months.

Habitat

The bluestreak cleaner wrasse is broadly distributed throughout the tropical and temperate Indo-West Pacific ocean realm. Its geographical range extends from the Red Sea, the Persian Gulf, and eastern Africa across the Indian Ocean to French Polynesia and the Tuamotus in the South Pacific. It is found as far north as southern Japan and as far south as southwestern Australia, the southern Great Barrier Reef, and the Kermadec Islands Marine Reserve north of New Zealand. This species inhabits shallow marine environments, predominantly occupying subtidal reef flats, coral areas, and seaward reef slopes. It is typically found in shallow waters at depths starting below 1 metre, where hard coral formations provide ideal structures for establishing permanent cleaning stations. These stations are positioned at conspicuous coral outcrops that client fish can easily identify and access. At night, the wrasse retreats into small crevices, holes, and cracks within the coral framework for safety, where it sometimes encases itself in a protective mucus cocoon to sleep.

Diet

The bluestreak cleaner wrasse is a specialized feeder whose diet primarily consists of ectoparasites (such as parasitic crustaceans), dead tissue, old scales, dirt, and fish mucus gleaned from client animals. Cleaning occurs strictly during daylight hours when client fish visit designated cleaning stations. The wrasse inspects the client's skin, fins, gill chambers, and mouth cavity, consuming unwanted organic matter while providing health and hydrodynamic benefits to the host. While it is an obligate cleaner in many parasite-dependent environments, its feeding habits vary geographically. In tidal reef environments like the Great Barrier Reef, it acts as a facultative cleaner, consuming significant amounts of live coral alongside client parasites and mucus. Juveniles generally feed on smaller parasites and have been observed biting client fish more frequently than adults do. The wrasse's client list is remarkably broad, encompassing reef teleosts (surgeonfish, damselfish, bullseyes, wrasses), giant moray eels, cartilaginous fishes (sharks and rays), lobsters, octopuses, sea turtles, and even large marine mammals such as balaenopterid whales.

Did You Know?

Fun Facts

Bluestreak cleaner wrasses have potentially passed the mirror self-recognition test, indicating high cognitive abilities.

All bluestreak cleaner wrasses are born female; if the dominant male dies, the largest female transforms into a male.

At night, cleaner wrasses sleep inside reef crevices, sometimes encasing themselves in a protective cocoon of mucus.

The sabretoothed blenny mimics the cleaner wrasse's blue-and-black pattern and dancing movement to bite flesh off unsuspecting fish.

Start Your Adventure

Ready to Dive with This Animal?

Explore our liveaboard expeditions to the best diving destinations