Bluehead
Thalassoma bifasciatum
(Bloch, 1791)
Description:
Terminal phase of male: Head blue, followed by two dark bars, separated by a white bar. Rear body yellowish, green to blue-green.
Size up to 25 cm.
Initial, juvenile phases and terminal phase of female cannot be distinguished by the color pattern or size. They display three basic patterns, all with a white belly and a black spot behind the third ray of the dorsal fin that does not reach the base of the fin. They can change from one to the other pattern rapidly, with intermediate color patterns between:
a. White vertical bars break the dark midbody stripe into series of rectangular blotches. Back yellowish to greenish or bluish.
b. Body with a solid midbody stripe from the snout to the tail. When swimming over reefs, the back is usually yellow, when swimming over sand or rubble, the back is usually white (T. bifasciatum juvenile).
c. Yellow head and body above the white belly, without a midbody stripe, but with two squarish spots behind the eye.
Habitat:
The young ones can be found everywhere in small schools on the reef, especially in shallow water. The larger males are more solitary and found to depths of 40 m. The smaller juveniles are often cleaning other fish.
Like in most wrasses sex-reversal also occur in the Bluehead. Small specimens are females, which change into males when growing. Males larger than 7 cm display the characteristics of the terminal phase. Reported age is three years.
Distribution:
Common south Florida and Bahamas; very common Caribbean.