The Redcheek Wrasse (Thalassoma genivittatum) is also known as the Dolphin wrasse from the juveniles resemblance to a Dolphin. This can be seen in the image below. They tend to favor the tops of semi protected shallow coral rich reefs. They are extremely active fish and are continuously feeding. They do not seem to have been recorded in Tanzanian waters before.
As with many wrasses the colouration changes from the adults to the juveniles. The juveniles as seen above have a dark upper body with a white lower body. There is a lighter line across the upper body from head to tail and the upper and lower edges of the caudal fin are orange or yellow.
As they mature into the female initial stage so the upper body goes a purplish red colour as do their cheeks and the lower body is a white colour with dark bands. In the terminal or male phase, the lower body goes a greenish colour and the purple-red becomes more bright on the cheeks.
REDCHEEK WRASSE IN THE WILD
The Redcheek wrasse are very active fish and cruise the reef at high speed. The juveniles are usually seen in large groups, often hiding in urchin spines as can be seen above or in branched corals. The females are normally solitary and may sometimes have groups of juveniles in the vicinity.
The Redcheek Wrasse has a very limited distribution and previously was only known to the Natal coast of South Africa, southern Mozambique and Reunion and Mauritius. This seems to be the first record from Tanzania. They favor shallower waters and are almost never seen deeper than 15 meters.
The Redcheek Wrasse feed on small benthic crustaceans and actively swim the reef picking off their prey from the substrate.
The Redcheek Wrasse is a Protogynous hermaphrodite, they first develop into females. Some larger specimens based on social cues transform into males. They are Oviparous, with the dominant male running a harem or at times several harems of females. Very little is known of their breeding habits but occasionally a dominant male will be seen pursuing a female.
Redcheek Wrasse are kept in aquariums but may become territorial towards similar sized fish and because of this are not commonly kept. They require good hiding places and plenty of water to swim in. A larger tank is therefore a prerequisite.