YELLOWTAIL (REDFIN) PARROTFISH: BAHAMAS REEF FISH (54)

The yellowtail parrotfish (sometimes known as a redfin) is one of around half-a-dozen kinds of parrotfish found among the coral reefs of the Bahamas, and sometimes in seagrass areas. There are many other related species worldwide (about 80). Parrotfish are among the most important fishes on the reef because they play a major role in BIOEROSION , a vital process for the health of the reef.

A. FEEDING & BEACH BUILDING

• Their dental arrangements – a mouthful of meshing teeth – form the characteristic ‘beak’
• Primarily herbivores but also snack on small creatures, organisms, or even molluscs
• As they feed on their favourite algae, their teeth grind up the coral which they ingest
• They digest the coral & excrete it as sand, becoming a component of your favourite beach
• The teeth grow continuously, replacing ones worn away by grinding coral as they graze
• They are a vital species in preventing algae from choking coral: essential reef cleaners

B. PARROTFISH: PERSONAL INFORMATION

• Some secrete a protective mucous cocoon to sleep in or as concealment from predators
• Mucous also helps to heal damage, repel parasites, & protect them from UV light
• As they develop from the juvenile stage, most species change colour significantly
• In some species, juveniles change colour temporarily for protective purposes
• These are “sequential hermaphrodites”, turning from female to male (‘protogyny’)
• Single males tend to have several lady friends, and aggressively defend their love rights
• Parrotfish are PELAGIC SPAWNERS. Females release many tiny buoyant eggs into the water
• The eggs float freely then eventually sink to the coral until they hatch
• Unlike almost all other fishes, they use their pectoral fins to propel themselves
• Feeding behaviour / dietary requirements make them (thankfully) unsuitable for aquariums (or aquaria, if you prefer)

WHAT WAS THAT ABOUT CHANGING SEX?

• Parrotfish may undergo sex reversal in which developing female fish become males
• Parrotfish born male remain male throughout their lives (“primary males”)
• Female-born fish may change sex & colour to become male (“secondary males”)
• Secondary males are fertile and generally mate with a single female
• Females that stay female live in harems protected by a dominant “supermale” BUT…
• …if the supermale dies, the largest female in the group changes sex to become male…
• …AND amazingly adopts the coloration of the supermale (best ‘astounding fact’ of all)

ARE PARROTFISH EDIBLE? JUST ASKING…

• Parrotfish skin is very tough but their flesh is soft and degenerates quickly
• Some species (eg blue parrotfish) carry ciguatera toxins – to be avoided
• They are not considered a fishing target in Bahamas, nor a food-fish
• Parrotfish are eaten elsewhere in the world however, for example Jamaica (cooked)
• In Hawaii they are eaten raw – at one time they were reserved for royalty

VIDEO LINK: PARROTFISH POOP

Credits: Melinda Rogers / Dive Abaco for her great illustrative images. All photographs were taken on the reefs of Abaco, before the devastation and destruction of Hurricane Dorian last September; Florida Museum to cross-check facts; VIDEO – Scientific American