Parrotfish

Most commonly found in the Indo-Pacific, these beautiful fish should be the first you look out for when diving in the beautiful coral reefs around Thailand. Parrotfish (members of the Scaridae family) are best known for their parrot-like beak and vividly bright colours.

It is estimated that there are between 80 and 95 different species of parrotfish due to the huge variety of colours and patterns. As their appearance can change throughout their lives, categorizing and identifying specific species is rather difficult.

Distinguishing Features

What many divers don’t realize is that the beak of the parrotfish is actually a number of fused teeth, used to pull algae from coral (a process known as bioerosion). The teeth are positioned on the external surface of the jaw bones and grow continuously throughout their life span.

Depending on the species, a parrotfish can grow between 30cm and 120cm by the time they reach maturity, although maximum sizes don’t vary much within individual species.

Habitat

Found in relatively shallow tropical and subtropical oceans around the world, parrotfish prefer to make their home around coral reefs, rocky coasts and seagrass beds. That’s because these habitats provide a constant and plentiful food supply.

Feeding Habits

Most species of parrotfish are herbivores and they spend 90% of their day eating algae and coral. An extra set of teeth (pharyngeal teeth) in the fish’s throat grinds up the coral so that algae particles can be extracted during digestion. However, there are many species that also eat the multitudes of microscopic organisms that live on coral reefs.

The feeding habits of coral fish are essential to the coral reef ecosystem. By eating the algae, parrotfish are preventing the coral from being suffocated. As the coral cannot be digested, the parrotfish excrete the undigested coral and it becomes sand.

Reproduction

Parrotfish have a very interesting method of reproduction. For unknown reasons, parrotfish change gender a number of times throughout their lives (sequential hermaphroditism). The females release hundreds of tiny eggs, which float freely and settle into the coral until they hatch.

Life Cycle

On average, parrotfish can live up to 7 years. They change colour and gender throughout their lives (polychromatism) depending on their particular development phase; juvenile, initial, or terminal. Parrot fish also tend to form large schools, presided over by a dominant male. If this male is removed, one of the females will change gender and adopt the dominant male role.

Parrot fish factoids

• At night, parrot fish cocoon themselves in transparent mucous secreted from their head. This is perhaps to mask their scent and protect them from nocturnal predators.
• These fish are rarely consumed except in Polynesia, where they were once considered the food of royalty.
• One parrot fish can chew and excrete 90 kg of coral per year.
• The disappearance of parrot fish would be detrimental to coral reefs, due to their contribution to the delicate ecosystem.