Labroides dimidiatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Perciformes Labridae

Scientific Name: Labroides dimidiatus (Valenciennes, 1839)
Regional Assessments:
Common Name(s):
English Blue diesel wrasse, Bluestreak cleanerfish, Blue-streak cleaner wrasse, Bluestreak cleaner wrasse, Bridled beauty, Cleaner wrasse, Wrasse
French Nettoyeur à bande bleue, Poisson doctère, Poisson nettoyeur commun
Cossyphus dimidiatus Valenciennes, 1839
Cossyphus dimidiatus Valenciennes, 1839
Labroides bicincta Saville-Kent, 1893
Labroides bicincta Saville-Kent, 1893
Labroides caeruleolineatus Fowler, 1945
Labroides caeruleolineatus Fowler, 1945
Labroides dimidatus (Valenciennes, 1839)
Labroides dimidatus (Valenciennes, 1839)
Labroides paradiseus Bleeker, 1851
Labroides paradiseus Bleeker, 1851
Labrus latovittatus Rüppell, 1835
Labrus latovittatus Rüppell, 1835

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2010
Date Assessed: 2008-05-12
Assessor(s): Shea, S. & Liu, M.
Reviewer(s): Craig, M.T. & Carpenter, K.E.
This species is abundant throughout the Indo-Pacific. Although it is intensively collected for the aquarium trade, it is not thought to be contributing to any widespread population decline. It is listed as Least Concern. More research is needed on sustainable harvest levels and the impact of collection on this species.

Geographic Range [top]

Range Description:This species is found in the Indo-Pacific from southern and eastern Africa and the Red Sea to the Tuamotus in the south Pacific, and from southern Japan to the southern Great Barrier Reef and south-western Australia.
Countries occurrence:
American Samoa; Australia; British Indian Ocean Territory; Cambodia; China; Christmas Island; Cocos (Keeling) Islands; Comoros; Cook Islands; Djibouti; Egypt; Eritrea; Fiji; French Polynesia; Guam; India; Indonesia; Iran, Islamic Republic of; Israel; Japan; Jordan; Kenya; Kiribati; Korea, Republic of; Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Mayotte; Micronesia, Federated States of ; Mozambique; Myanmar; Nauru; New Caledonia; Niue; Norfolk Island; Northern Mariana Islands; Oman; Palau; Papua New Guinea; Philippines; Pitcairn; Réunion; Samoa; Saudi Arabia; Seychelles; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Tokelau; Tonga; Tuvalu; United Arab Emirates; United States Minor Outlying Islands; Vanuatu; Viet Nam; Wallis and Futuna; Yemen
FAO Marine Fishing Areas:
Atlantic – southeast; Indian Ocean – western; Indian Ocean – eastern; Pacific – eastern central; Pacific – northwest; Pacific – southwest; Pacific – western central
Additional data:
Lower depth limit (metres):40
Upper depth limit (metres):1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is common in many parts of its range.

It is common in the southern coral areas of the Ryukyu Islands and Ogasawara Islands (Kataoka et al. 1970), on the inshore rocky reefs, whereas it does not live on the sand or pebble areas (Kuwamura 1981). The populations increased in summer and autumn, but decreased in winter, sometimes nearly zero. About 0.9 individuals per 100 m2 have been recorded at rocky reefs at Shirahama (Kuwamura 1981).

It is common in the Capricorn/ Bunker Group, One Tree and Heron Islands and Wistari Reef, Fairfax, Fitzroy, Llewellyn and Musgrave Islands on the Great Barrier Reef, with 1.77 recruits per 100m2 (Eckert 1984).

In Australia, it was found to be one of the most abundant labrids at Lizard Island, GBR (three individuals per 150 m2) and occurred in similar densities in all habitat zones (Green 1996).

In Hong Kong, it is common in shallow areas of boulders and coral areas, but never abundant (Sadovy and Cornish 2000).

In Fiji, a total of 475 individuals were observed in various UVC surveys with body sizes of 4-17 cm TL (M. Kulbicki pers. comm. 2008).

In New Caledonia, a total of 1,407 individuals were observed in various UVC surveys with body sizes of 3-22 cm TL. In 31 stations, a total of 58 individuals were caught with a total weight of 242.1 g (M. Kulbicki pers. comm. 2008).

In French Polynesia, a total of 568 individuals were observed in various UVC surveys with body sizes of 4-12 cm TL (M. Kulbicki pers. comm. 2008)

In Tonga, a total of 205 individuals were observed in various UVC surveys with body sizes of 3-11 cm TL (M. Kulbicki pers. comm. 2008).

Mean density was 1.5 fish per 100 m2 on coral reefs of the Adang-ra Wi Islands in the Adaman Sea (Satapoomin undated).

It is common at Enewetak Atoll, Marshall Islands (Colin and Bell 1991), Solomon Islands (Allen 2006) and in the Red Sea (Richard and Field 1998).

In Pangkor Island, Malaysia an estimated mean density of 0.33 individuals from three 100 m X 2 m transects was recorded in underwater fish visual surveys (Y. Yusuf unpublished data).

On the east coast of Peninsular Malaysia, an estimated mean density of 4.55 individuals from twenty 50 m X 5 m transects was recorded in underwater fish visual surveys (Yusuf et al. 2002).
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species inhabits coral rich areas and subtidal reef flats to seaward reefs to depths of at least 40 m. It is widely reported to be a monandric hermaphrodite but further confirmed to display bi-directional sex-change, exhibits socially controlled sex reversal and lives in single-male, multiple female social groups (Kuwamura 1984, Sadovy and Cornish 2000, Kuwamura et al. 2002, Sadovy de Mitcheson and Liu 2008). Males exhibit territoriality and the largest, oldest individual is a male which dominates all the females in the group (Robertson 1972, Nakashima et al. 2000).

It feeds on crustaceans ectoparasites and mucus of fishes which gather at specific cleaning ‘stations’ for attention (Pott 1973). Males and females are the same in colour, juveniles are black with a single blue stripe running from snout to the upper part of caudal fin.

It is active in daytime and is reported to be able to produce a protective mucous cocoon at night. Seasonal fluctuation of the activity rate has been observed with almost all individuals always active during late spring and early summer (Kuwamura 1981).

In Japan, spawning occurred within 4-5 months of the year, from late May to early September. Larvae of about 1.8 mm in total length hatch at 30 hours after spawning (Kuwamura 1981).

This species is monochromatic, spawns in harem. Spawning ascent distance was about three m with rapid ascending speed. Spawning activities were seen in March, May, June and November at Enewetak Atoll, Marshall Islands (Colin and Bell 1991). The size of eggs is approximately 0.64 mm and spherical in shape. Eggs contained multiple oil globules

Maximum size of species has been recorded at 22 cm (TL) in New Caledonia and maturity is reached at a size of about six cm TL (Kuwamura 1981, M. Kulbicki pers. comm.). All of the larger adults have an almost completely developed ventroanterior hook in the caudal fin. Maximum lifespan is estimated to be four years (Allsop and West 2003) and minimum population doubling time is approximately 1.4-4.4 years (Froese and Pauly 2008).

It shows cleaning behaviour, which only occurs during the day and particularly in the early morning (Grutter 1996). In captivity it is affected by abundance and size-frequency distribution of the monogenean parasites on the host of fishes, which was more pronounced on larger fish than on small fish (Grutter et al. 2002). It spends 60 to 154 more times cleaning larger fishes (> 12.5 cm SL) than medium (9.5 to 12.5 cm SL) or small sized fish (< 9.5 cm SL). In the Great Barrier Reef, it was found to spend 256 +/- min per day cleaning 2297 +/- 83 fish (Grutter 1996) from over 132 species (Grutter and Poulin 1998). In New Caledonia, it spent 26% of its time inspecting a large number of fish (59.5 +/- 5.1 per 15 minute) (Grutter 1999).

It consumes a large number of parasites (1218 +/- 118) each day or 4.8 +/- 0.4 parasites per minute (Grutter 1996) and most of the prey items were juvenile gnathiid isopods (Grutter 1997). The biomass of gnathiids in the diet in New Caledonia was lower than at Lizard Island, but higher than at Heron Island, suggesting that the role of gnathiids in cleaning behaviour is variable (Grutter 1999).

At One Tree Lagoon on the Great Barrier Reef, overall mortality during first year for L. dimidiatus was 50%, juveniles do not shelter within the substratum and displayed relatively high mortality over the first twelve months (Eckert 1987). The average annual mortality ofL. dimidiatus was 11.1 +/- 2.2 %.

Use and Trade [top]

Use and Trade: This species is heavily targeted for the aquarium trade, especially for its cleaning behaviour (Kuwamura 1976).

In Sri Lanka, about 20,000 individuals were exported annually, it is considered as a top export species in the marine ornamental trade (Wood and Rajasuriya 1999, Ekaratne 2000, Wood 2001). Due to its ‘cleaning service’ behaviour, there are concerns at the high aquarium trade for L. dimidiatus and other Labroides species, which may have negative impacts on the health of other reef fishes (Edward and Shepherd 1992).

Threats [top]

Major Threat(s): There are no major threats known for this species, although it is targeted for the aquarium trade and there are occuring coral habitat degradation in parts of its range.

Conservation Actions [top]

Conservation Actions: There are no specific conservation measures in place for this species. Its distribution overlaps several marine protected areas within its range.

This species has been observed at protected areas on the Great Barrier Reef, Australia (Hutchins and Sawinston 1996), at Ras Mohammed National Park, Egypt (Bshary 2003) and in the Mafia Island Marine Park, Tanzania (Garpe and Öhman 2003). Given the intensive collection of this species for the aquarium trade, more research is needed on the local and global impact of collection, as well as on the implementation of sustainable harvest and trade measures.

Classifications [top]

9. Marine Neritic -> 9.2. Marine Neritic - Subtidal Rock and Rocky Reefs
9. Marine Neritic -> 9.8. Marine Neritic - Coral Reef -> 9.8.2. Back Slope
9. Marine Neritic -> 9.8. Marine Neritic - Coral Reef -> 9.8.3. Foreslope (Outer Reef Slope)
12. Marine Intertidal -> 12.1. Marine Intertidal - Rocky Shoreline
3. Species management -> 3.1. Species management -> 3.1.1. Harvest management
3. Species management -> 3.1. Species management -> 3.1.2. Trade management

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over entire range
In-Place Species Management
In-Place Education
1. Research -> 1.2. Population size, distribution & trends
3. Monitoring -> 3.1. Population trends

♦  Pets/display animals, horticulture
 National : ✓  International : ✓ 

Bibliography [top]

Allen, G.R. 2006. Coral Reef Fish Diversity. In: A. Green, P. Lokani, W. Atu, P. Ramohia, P. Thomas and J. Almany (eds), Solomon Islands Marine Assessment: Technical report of survey conducted May 13 to June 17, 2004. TNC Pacific Island Countries Report No. 1/06. The Nature Conservancy.

Allsop, D.J. and West, S.A. 2003. Constant relative age and size at sex change for sequentially hermaphroditic fish. Journal of Evolutionary Biology 16: 921-929.

Bashary, R. 2003. The cleaner wrasse, Labroides dimidiatus, is a key organism for reef fish diversity at Ras Mohammed National Park, Egypt. Journal of Animal Ecology 72(1): 169-176.

Colin, P.L. and Bell, L.J. 1991. Aspects of the spawning of labrid and scarid fishes (Pisces: Labroidei) at Enewetak Atoll, Marshall Islands with notes on other families. Environmental Biology of Fishes 31(3): 229-260.

Donnelly, R., Neville, D. and Mous, P. 2003. Report on a rapid ecological assessment of the Raja Ampat Islands, Papua, Eastern Indonesia, held October 30 – November 22, 2002. The Nature Conservancy, Sanur, Bali, Indonesia.

Eckert, G. 1987. Estimates of adults and juvenile mortality for labrid fishes at One Tree Reef, Great Barrier Reef. Marine Biology 95: 167-171.

Edwards, A.J. and Shepherd, A.D. 1992. Environmental implications of aquarium-fish collection in the Maldives, with proposals for regulation. Environmental Conservation 19: 61-72.

Ekaratne, S. 2000. A review of the status and trends of exported ornamental fish resources and their habitats in Sri Lanka. BOBP/REP/88.

Field, R. and Field, M. 1998. Reef fishes of the Red Sea – A guide to Identification. Kegan Paul International, London.

Froese, R. and Pauly, D. 2007. FishBase version (10/2007). Available at:

Garpe, K.C. and Öhman, M.C. 2003. Coral and fish distribution patterns in Mafia Island Marine Park, Tanzania: fish-habitat interactions. Hydrobiologia 498: 191-211.

Green, A. 1996. Spatial, temporal and ontogenetic patterns of habitat use by coral reef fishes (Family Labridae). Marine Ecology Progress Series 133: 1-11.

Grutter, A. 1996. Parasite removal rates by the cleaner wrasse Labroides dimidiatus. Marine Ecology Progress Series 130: 61-70.

Grutter, A. 1999. Fish Cleaning behaviour in Noumea, New Caledonia. Marine and Freshwater Research 50: 209-12.

Grutter, A. and Poulin, R. 1998. Intraspecific and interspecific relationships between host size and the abundance of parasitic larval gnathiid isopods on coral reef fishes. Marine Ecology Progress Series 164: 263-271.

Grutter, A.S. 1997. Spatio-temporal variation and feeding selectivity in the diet of the cleaner fish Labrodies dimidiatus. Copeia 1997(1): 346-355.

Grutter, A.S., Deveney, M.R., Whittington, I.D. and Lester, R.J.G. 2002. The effect of the cleaner fish Labroides dimidiatus on the capsalid monogean Benedenia lolo parasite of the labrid fish Hemigymnus melapterus. Journal of Fish Biology 61(5): 1098-1108.

Hutchins, B. and Sawinston, R. 1999. Sea fishes of southern Australia: complete field guide for anglers and divers. Gary Allen Pty Ltd., Smithfield, N.S.W.

IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.4). Available at: (Accessed: 27 October 2010).

Kataoka, T., Kitamura, S., Sekido, M. and Yamamoto, K. 1970. Coral fishes of the Ogasawara (Bonin) Islands. Report on the Marine Biological Expedition to the Ogasawara (Bonin) Islands, 1968. Toba Aquarium, Asahi Shinbun Pub. Comp.

Kuwamura, R. 1981. Life history and population fluctuation in the Labrid fish, Labroides dimidiatus, near the northern limit of its range. Publications of the Seto Marine Biological Laboratory 26: 95-117.

Kuwamura, T. 1976. Different responses of inshore fishes to the cleaning wrasse, Labroides dimidiatus, as observed in Sirahama. Publications of the Seto Marine Biological Laboratory 23: 119-144.

Kuwamura, T. 1984. Social structure of the protogynous fish Labroides dimidiatus. Publications of the Seto Marine Biological Laboratory 29: 117-177.

Kuwamura, T., Tanaka, N., Nakashima, Y., Karino, K. and Sakai, Y. 2002. Reversed sex-change in the protogynous reef fish Labroides dimidiatus. Ethology 108: 443-450.

Nakashima, Y., Sakai, Y., Karino, K. and Kuwamura, T. 2000. Female-female spawning and sex change in a haremic coral-reef fish, Labroides dimidiatus. Science 17: 967-070.

Potts, G. 1973. The ethology of Labroides dimidiatus (Cuv. & Val.) (Labridae, Pisces) on Aldabra. Animal Behavior 21: 250-291.

Robertson, D.R. 1972. Social control of sex-reversal in a coral reef fish. Science 177: 1007-1009.

Sadovy de Mitcheson, Y. and Liu, M. 2008. Functional hermaphroditism in teleosts. Fish and Fisheries 9: 1-43.

Sadovy, Y. and Cornish, A.S. 2000. Reef fishes of Hong Kong. Hong Kong University Press, Hong Kong.

Satapoomin, U. 2002. Patterns of fish assemblages on coral reefs of the Adang-rawi Islands, the Andaman Sea, with comments on management implications for coral reef reserves. Natural History Bulletin of the Siam Society 50(1).

Wood, E. 2001. Collection of coral reef fish for aquaria: global trade, conservation issues and management strategies. Marine Conservation Society, Ross-on-Wye, U.K.

Wood, E. and Rajasuriya, A. 1999. Sri Lanka Marine Aquarium Fishery Conservation and Management Issues. Marine Conservation Society and National Aquatic Resources Agency.

Yusuf, Y., Ali, A.B. and Mohd. Ibrahim, H.M. 2002. Coral reef fish of Pulau Payar and Pulau Perhentian. Proceedings of the Fourth Regional IMT-GT Uninet Conference 2002: 427-431. Penang, Malaysia.

Citation: Shea, S. & Liu, M. 2010. Labroides dimidiatus. The IUCN Red List of Threatened Species 2010: e.T187396A8523800. . Downloaded on 17 August 2018.
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