The blue-barred parrotfish, 𝘚𝘤𝘢𝘳𝘶𝘴 𝘨𝘩𝘰𝘣𝘣𝘢𝘯 (Forsskål, 1775) is a species of parrotfish (Scaridae family) present predominantly in Indo-Pacific waters. 🌏 Blue-barred parrotfish live up to 13 years and grow to around 45 cm, whereas other species of parrotfish can reach a whopping 1.2 m in length!
Parrotfish, like other groups of fishes such as wrasses (Labridae family), have astonishing reproductive biology known as protogynous hermaphrodites. This means that most are born female and then, if the need arises, they can change their anatomy, colouration and behaviour dramatically to become males. Normally a larger, colourful male will defend and provide sperm for a group of smaller, less gaudy females. As these grow, or when the lead male dies, the largest females will turn male and challenge one another for control of the group. In very large groups, sometimes a small, dull male that looks like a female will emerge, and be able to sneakily spawn with the females without the leader’s notice. 😮 Soap-level drama!
Many species of parrotfish, including the blue-barred, create a transparent bubble or cocoon made of mucus secreted from glands in their gills. They surround themselves in this at night to protect themselves from parasites such as isopods and mask their scent from sharks and other predators, keeping them safe while they sleep. 💤 The rest of their time is spent munching away.
🦜 Parrotfish get their name from their large dental plates that look like buck teeth or beaks. These sharp plates are fused to their jawbones and are stronger than many metals, plus they have further teeth inside their throats (pharyngeal jaw). This artillery of grinders is crucial as parrotfish feed on algae growing on and polyps that make up coral. 😋 In order to get to the yummy, useful bits, they scrape and munch (up to 20 bites a minute!) on the algae and coral which is largely made of calcium carbonate and then poop out the broken down sand that’s left over after digestion. If you swim behind a feeding parrotfish you can see the plume of fine sand being pushed out, and it’s estimated that a single parrotfish can poop over 90kg of sand a year! Scientists used to worry parrotfish caused coral reef destruction but we now know that they recycle bleached coral and overall maintain the health of threatened coral reefs, as well as creating lots of lovely new poopy sand. They’re responsible for creating whole new reef islands! 🏝️ Imagine your waste being that pleasant.
Some species of parrotfish are endangered due to overfishing. ⚠️ They are considered a delicacy in some places such as the Pacific Islands, in some of which the bumphead parrotfish has been fished to extinction. 😔 The bumphead is an extra freaky species as, not only does it chew coral, but before it does, it swims into it at speed, knocking it hard with its bulging head bump, loosening bits off and eating those, which are more easily digestible. 🐏
Have a look at the blue-barred parrotfish specimen at the HKBM. This species has many different names referring to the intricate and shiny patterns and colours of its scales: cream parrotfish, green blotched parrotfish, yellow scale parrotfish, bluechin parrotfish... 🎨 So as you can imagine, it normally looks a lot more interesting and shimmery than it does now, but you can still come to have a look at its mighty chompers! 🦷
Text: Elvira Rey Redondo
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