Thalassoma jansenii

Jansens wrasse | Thalassoma janseni
Thalassoma jansenii
Thalassoma jansenii, Bali, Indonesia, Photo: Ian Shaw
Thalassoma jansenii
Thalassoma jansenii, Raja Ampat, Indonesia, Photo: Andrew Green
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Thalassoma jansenii
Thalassoma jansenii


Tropical Indo-Pacific


Pectoral fins proportionally shorter than in T. nigrofasciatum, and juveniles with more light bars (often 5-6). Otherwise difficult to distinguish within overlapping range in the SW Pacific [Note that most records from the Australian east coast are likely Thalassoma nigrofasciatum, however, needing correction in the database].


Max Size: 20 cm

Sea Temperature Range: 19.8-31.3°C

Depth: 1-15m

Habitat Generalization Index: 13.81

Also referred to as the SGI (Species Generalisation Index), this describes the habitat niche breadth of the species. Species with values less than 15 are found in a relatively narrow range of reef habitat types (specialists), while those over 25 may be found on most hard substrates within their range (generalists). Learn more here.

Conservation and Rarity

IUCN Status: Least Concern

Occurrence: Frequent (12.4% of sites)

Occurrence describes how often the species is found on surveys within its distribution. It is calculated as the % of reef sites surveyed by RLS divers across all the ecoregions in which the species has been observed

Abundance: Several (6 per transect)

Abundance is calculated as the average number of individuals recorded per RLS transect, where present.