Moon Wrasse
Thalassoma lunare
One of the more common and colourful inhabitants of tropical reefs in WA. The green colouration with bluish stripes on the sides and magenta lines on the head and a patch of the same colour centrally on the pectoral fins are distinctive. The common name is in reference to the bright yellow patch in the middle of the caudal fin (or tail), which gives the appearance of a cresent moon. Juveniles are olive green with a blue belly and large dark spot at the base of the tail.
Morphology
An elongate fish with a steep to rounded snout profile. The single dorsal fin runs the entire length of the back and the caudal fin is distinctly lunate (or crescent shaped) in adults and truncate (squared off) in juveniles. Best distinguished from some similar looking congeners (e.g. T. lutescens) by the pectoral fin colouration. The maximum reported size is 45 cm but specimens greater than 30 cm are rare.
Evolution
A member of the highly diverse wrasse family Labridae, which contains about 530 species. Currently, 28 species of Thalassoma are recognised globally, with some evidence reported of hybridisation occurring between species including T. lunare.
Behaviour
Occurs solitary or sometimes in small groups that are active during daylight hours, retreating to the shelter of reef crevices and branching corals at night. Like many wrasses, the pectoral fins are used to assist in propulsion whilst swimming. Consumes small benthic invertebrates and fish eggs. Spawns in pairs or in small aggregations.
Method of reproduction
Sexual; a protogynous hermaphrodite with individuals born as females that change sex at around 3 years of age (~12 cm).
Habitat
Marine
Coral or rocky reefs, from 1-20 m depth.
Distribution
Occurs in tropical and sub-tropical marine waters throughout the Indo-Pacific region, from East Africa and the Red Sea to the islands of the central Pacific. In Western Australia it can be found as far south as Rottnest Island.
Life Cycle
Oviparous
| Kingdom: | Animalia |
|---|---|
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Perciformes |
| Family: | Labridae |
| Genus: | Thalassoma |
| Species: | lunare |
| Name Published Year: | 1758 |
|---|---|
| Scientific Name Authorship: | <i>Thalassoma lunare</i> |
| Commercial Impact: | Commonly captured for the aquarium fish trade. |
| Conservation Assessment: | Least Concern |
Cite this page
Western Australian Museum Collections https://museum.wa.gov.au/online-collections/names/Thalassoma-lunare
Accessed 30 Apr 2025
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