Bluehead Wrasse - Jessica Miller

Two bluehead wrasse, Thalassoma bifasciatum, the one on the right is an initial phase,

the one on the left is a terminal phase.

Initial phase Thalassoma bifasciatum

Initial phase Thalassoma bifasciatum

Bluehead wrasse (Thalassoma bifasciatum) are a small species of saltwater fish that are native to coral reefs in the western Atlantic and the southeast area of the Gulf of Mexico, including the tropical waters surrounding the Florida Keys. These small wrasse are less then 110m standard length, on average. The blue head wrasse eat zooplankton, mollusks and other small crustaceans including parasites on other fish.They are an important cleaner fish on the reef and form large schools. Like most other wrasse they have several different phases, their initial phase when they are juveniles has a yellow upper body and a white lower body. The initial phase may also have green or black lateral stripes or dark vertical bars. 

Bluehead wrasse can quickly change their appearance and intensity of the colors on their bodies, it is thought to be related to behavioral changes. The terminal phase of both males and females has a blue head, green body and black and white vertical bars behind its head. Bluehead wrasse are protogynous sequential hermaphrodite; individuals may begin life either as males or females, but females can change sex later in life and become males. This change is permanent and once an initial phase female or male turns into a terminal phase male they cannot change back. 

Terminal phase Thalassoma bifasciatum