How to Identify Moon Wrasse

To identify Moon Wrasse (Thalassoma lunare), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Initial phase (females and juvenile males) are typically green to greenish-blue with a prominent dark stripe running horizontally along the body, often broken into spots. Terminal phase males are more intensely colored, with a vibrant green body, a pinkish-red band on the head, and often a vertical red bar behind the pectoral fin. The caudal fin is distinctly crescent-shaped, with elongated lobes, and is typically yellow to orange with blue or green margins.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Crescent-shaped caudal fin with elongated lobes, Vibrant green body coloration in terminal phase males, Dark horizontal stripe (often broken) in initial phase, Small, pointed snout

Dorsal fin

Single dorsal fin with 8 spines and 13 soft rays. The spinous and soft-rayed portions are continuous.

Tail fin

Lunate (crescent-shaped) with elongated upper and lower lobes. Typically yellow to orange with blue or green margins.

Pectoral fin

Large and fan-like, used for propulsion and maneuvering. Typically clear to yellowish.

Distinctive fins

The caudal fin's deeply emarginate to lunate shape is a key diagnostic feature, especially in larger individuals.

Identification Tips

1. 1

   Caudal Fin Shape

   Look for the distinctive crescent-shaped (lunate) tail with elongated upper and lower lobes. This is the most reliable identifier, especially in adults.

2. 2

   Coloration (Terminal Male)

   Vibrant green body with a pinkish-red band on the head and a vertical red bar behind the pectoral fin. The caudal fin will be yellow/orange with blue/green edges.

3. 3

   Coloration (Initial Phase)

   Greenish body with a dark, often broken, horizontal stripe along the flank. The caudal fin will still show the crescent shape, though less pronounced than in terminal males.

4. 4

   Behavior

   Active, fast-swimming fish often seen darting among corals and rocks. They are diurnal and will bury themselves in the sand at night.

Explore Moon Wrasse