Stoplight Parrotfish

The new species in the stop… eh… spotlight is the Spot… eh… Stoplight Parrotfish (Sparisoma viride).

This fish is one of the main grazers of our beautiful reefs and performs a very important role, preventing the algae from overgrowing the corals. Both the males and females have a very distinct colour pattern, which makes them hard to miss during a dive. If you pay close attention you can even hear them taking bites out of the reef. They digest the algae and loose the calcium carbonate, of which the skeleton of the reef is built up, through their gills. Some corals survive this ordeal and land elsewhere on the reef to start a new colony of their own. In this way the Stoplight Parrotfish also helps to disperse the reefs. It is found in the Wider Caribbean region and in all of the six Dutch Caribbean islands. This species typically reaches a size of around 40 cm (~15.7″) in adulthood with an absolute maximum of 60 cm (~23.6″).

The Stoplight Parrotfish, like many other reef fish species, uses mangroves and seagrass beds as nursery grounds and when the juveniles are big enough, they migrate back to the reefs to start the next stage in their life cycle.

All Stoplight Parrotfish are born as females. They grow and change colour multiple times in their life: from a dark-brown with several white spots at birth, to a more colourful pattern with a marbled head, a checkered pattern of dark-brown and white scales and bright red fins, tail and underside as a mature female. This is called the ‘initial stage’. Then something remarkable happens: the mature female changes into a bi-coloured male with a blue/green head, bright green scales and a large yellow spot above the gills, which is what gives the fish its name: Stoplight Parrotfish. Given more time, the males will transform into a so-called ‘supermale’ with beautiful colours (see photo). This is called the ‘terminal stage’. This whole process of gender change over a lifetime is called ‘protogyny’ and occurs in a lot of fish species.

Photo Credit: © 2012 Chuck Shipley
 
Sources:
Arkive
FishBase