SpinyheadPlay freeBluehead wrasse Thalassoma bifasciatum
The bluehead wrasse is one of the most abundant and conspicuous small fishes on Caribbean reefs. Males in the terminal phase have a brilliant blue head, a black and white band behind the head, and a green body, while the far more numerous initial-phase fish are yellow or whitish with a dark stripe. It swims constantly by flapping its pectoral fins, often in loose groups over reef tops. It also acts as a cleaner when young, picking parasites from larger fishes.
How to recognize it
- bright blue head on large males
- black and pale bands behind the head on large males
- green rear body on large males
- yellow body with dark side stripe on small fish
- small, slender, torpedo-shaped body
- rounded tail in young fish, with tail edges often extended in large males
- swims by flapping pectoral fins
| Size | Most seen are about 5 to 10 cm long; maximum is about 15 cm. |
|---|---|
| Range | Tropical western Atlantic, from Florida, the Bahamas and Bermuda through the Caribbean to northern South America, and into the Gulf of Mexico. |
| Habitat | Found on coral reefs, rocky areas and seagrass beds, usually from very shallow water down to about 30 m or somewhat deeper. Terminal-phase males often hold spawning sites at reef edges or other prominent spots, while smaller fish forage over the reef. |
| Diet | Eats mainly small invertebrates such as small crustaceans, plus zooplankton picked from the water. Young fish also remove parasites from other fishes at cleaning stations. |
| Conservation | The bluehead wrasse is common and widespread. It is assessed as Least Concern by the IUCN. It is collected in small numbers for the aquarium trade, and coral reef decline is a potential threat to its habitat. |
Life and behavior
Bluehead wrasses are protogynous hermaphrodites, meaning individuals begin life as female or initial-phase fish and some later change into terminal-phase males. Some initial-phase fish are born male and never develop the blue-head colors. Large terminal-phase males defend spawning sites and mate with females in daily spawning rushes. Eggs are pelagic and drift in open water, and the larvae spend weeks in the plankton before settling on reefs. Individuals sleep at night, sometimes buried in sand, and can be seen again after dawn.
Its family: Wrasses (Labridae)
Wrasses are a large and varied family of mostly small to medium reef fishes. Many swim mainly with their pectoral fins and have strong, separate teeth in the front of the mouth. Many species change sex and have very different color patterns by age or sex. Several species act as cleaners.
Similar species
- Yellowhead wrasse Halichoeres garnoti Juveniles are yellow with a blue stripe, and adults have a yellow head with a darker rear body, not a blue head with a black and white band.
- Creole wrasse Clepticus parrae It is mainly purple-blue and feeds in schools above the reef, rather than having a blue head, pale band and green body.
- Slippery dick Halichoeres bivittatus It has a greenish body with dark stripes and lacks the vivid blue head and banded pattern of the terminal-phase bluehead.
