Specimen of the Week: Week 109
By Emma-Louise Nicholls, on 11 November 2013
Having waved goodbye with a heavy heart to the baby eagles that hatched on my balcony and fledged during the summer, Saruman (hamster) and I were alone. Don’t get me wrong, he keeps me busy. He is as naughty as a mammal gets. The other day after an episode of particularly noteworthy naughtiness, I put Return of the King on the television and showed him exactly what happens to Sarumans that misbehave but instead of admitting the error of his ways and repenting, he went to bed and ignored me for the rest of the evening. Sigh. Anyway, despite having the right hand of Sauron keeping me on my toes, I felt the need to expand my family. Let me therefore introduce you to General Grievous, Darth Maul, Mumm-Ra and Grun the Destroyer – my new variable platyfish (picture to follow). We don’t have this species at the Museum but in their honour I will tell you about something else a little fishy. This week’s Specimen of the Week is…
**The humphead parrotfish**
1) The humphead parrotfish is named for its smooth, planar, un-noteworthy forehead. Ok that’s a lie. These blue-green-grey-silver fish have a HUGE yellow or pink head. This is only in the adults however, so really the juveniles should be classified separately under the common name of not-very-humpheaded-humphead-parrotfish. That means the one we have is quite young as its forehead is underdeveloped (see image right). Juveniles also have a number of vertical rows of white spots, which makes two reasons why they are more attractive than the adults. In the vein of descriptive common names, parrotfish are so called due to their teeth which have fused to form a parrot like beak. They also have internal teeth at the back of the mouth with which they grind their hard shelled prey.
2) Parrotfish eat coral, live coral I should add, as well as algae from the sea-bottom. It uses the large hump on its head to smack into the coral which has the inelegant but effective result of breaking the coral into smaller, more mouth sized pieces. Any un-nutritious material that is too hard to grind and digest is passed out of the rear end of the fish in the normal fashion. This diet makes the humphead parrotfish a strong influence on the structure of coral reefs, especially given that one adult will eat between five and six tonnes of coral in a year. That is a lot of grinding.
3) Just like my beautiful platys (as in these, not these), humphead parrotfish like to live with others of their kind and are subsequently most commonly found in small shoals (hence I have four new additions to my family rather than the one I was aiming for). With humphead parrotfish however, these shoals can reach up to 75 individuals.
4) Unlike many species in the natural world that have a mating season each year, humphead parrotfish have one every month. Maybe that’s why they’re such happy fish*. They may have a touch of Twilight fever as they meet for sexy shenanigans in the early morning, normally during the full moon. It’s not so much a romantic candlelight meal for two, but rather more Eyes Wide Shut. The females will release eggs into the water which then get fertilised by sperm released by the males. Up to 100 individuals will make up any one of these groups.
5) As is common, but not the rule, a fish of this pretty colour and ‘funny looks’ belongs in tropical and subtropial regions, where they inhabit coral reefs. No suprise there given their diet. They inhabit reefs in the central and western Pacific, as well as the Indian Ocean and the Red Sea. Although during the day they can be found chomping their way through coral reefs, at night-time they retire to caves or rest in sheltered lagoons.
Emma-Louise Nicholls is the Curatorial Assistant at the Grant Museum of Zoology