Jansen's Wrasse, Thalassoma jansenii (Bleeker 1856)

Jansen’s Wrasse, Thalassoma jansenii, at Kadavu, Fiji. Source: Paddy Ryan / www.ryanphotographic.com/. License: All rights reserved

Often confused with the related Blackbarred Wrasse, Thalassoma nigrofasciatum, which occurs on the Great Barrier Reef and islands and reefs in the Coral and Tasman seas.

Cite this page as:
Dianne J. Bray, Thalassoma jansenii in Fishes of Australia, accessed 03 Dec 2023, https://fishesofaustralia.net.au/home/species/285

Jansen's Wrasse, Thalassoma jansenii (Bleeker 1856)

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Recorded in Australia from Scott Reef, Western Australia, and Ashmore Reef in the Timor Sea; also at Christmas and Cocos (Keeling) islands. Found elsewhere in the Indo-west-Pacific, from the Maldives to Micronesia and Japan.

Inhabits coastal, lagoon and outer reefs, often in areas exposed to surge on seaward and lagoon reefs in depths to 15 m.


Very closely related to Thalassoma nigrofasciatum, and the molecular sequences of 16S rRNA in the two species are the same, though they differ in one nucleotide of the cytochrome b sequence (Bernardi et al. 2004). Although there are no significant colour differences between these two species, and they have overlapping scale counts, they are both considered to be valid species.


Dianne J. Bray

Jansen's Wrasse, Thalassoma jansenii (Bleeker 1856)


Allen, G.R., N.J. Cross, C.J. Allen & M.F. Gomon 2006. Labridae: Labrinae. pp. 1368-1418 in Beesley, P.L. & Wells, A. (eds). Zoological Catalogue of Australia. Volume 35 Australia : ABRS & CSIRO Publishing Parts 1-3, 2178 pp.
Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp.

Allen, G.R. & R.C. Steene. 1988. Fishes of Christmas Island Indian Ocean. Christmas Island Natural History Association, Christmas Island, Indian Ocean, 6798, Australia. 197 pp.

Allen, G.R. & W.F. Smith-Vaniz. 1994. Fishes of the Cocos (Keeling) Islands. Atoll Research Bulletin 412: 21 p.

Bernardi, G., Bucciarelli, G., Costagliola, D., Robertson, D.R. & Heiser, J.B. 2004. Evolution of coral reef fish Thalassoma spp. (Labridae). 1. Molecular phylogeny and biogeography. Marine Biology 144: 369-375.

Cabanban, A. & Pollard, D. 2010. Thalassoma jansenii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. . Downloaded on 16 March 2014.

Kuiter, R.H. 1992. Tropical reef-fishes of the western Pacific Indonesia and adjacent waters. Gramedia Pustaka Utama, Jakarta.

Kuiter, R.H. & Tonozuka, T. 2001. Pictorial guide to Indonesian reef fishes. Part 2. Fusiliers - Dragonets, Caesionidae - Callionymidae. Zoonetics, Australia.

Randall, J.E. 2003. Thalassoma nigrofasciatum, a new species of labrid fish from the south-west Pacific. Aqua J. Ichthyol. Aquat. Biol. 7(1): 1-8.

Westneat, M.W. 2001. Labridae. Wrasses, hogfishes, razorfishes, corises, tuskfishes, pp. 3381-3467. In: K.E. Carpenter & V.H. Niem (eds). FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Vol 4. FAO, Rome.

Quick Facts

CAAB Code:37384166

Biology:Capable of changing sex

Conservation:IUCN Least Concern

Depth:1-15 m

Habitat:Reef associated

Max Size:20 cm TL

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