If there ever were a fish on a coral reef that deserved special attention this time of year, it would be the hou, or Christmas wrasse.
This fish doesn't bear any resemblance to Santa or any of his elves. It doesn't resemble anything like a pine tree, a gift or even have a red nose like Rudolph. No, this fish's festive name was derived from its place of scientific discovery in 1801, Christmas Island. Since then it has been seen throughout the Indo Pacific sporting its eye-catching red-and-green pattern; also synonymous with the upcoming holiday.
With 43 members, the wrasse family is arguably one of the most diversely colorful families of fish swimming on reefs in Hawaii. With their various ornate patterns, these fish are among the most difficult to identify, and the Christmas wrasse is no exception.
The striking green-and-red pattern on the Christmas wrasse is commonly thought to be the reason for its festive name. However, the
Christmas wrasse was actually named after the place it was first discovered 212 years ago, Christmas Island, and not after its holiday appearance.
Extending the length of its red body is a repetitive pattern of small vertical green rectangles. Four thick green stripes stretch from the dorsal ridge merging with every fourth green rectangle, but this describes only the terminal males. As with other species of reef fish, the color and pattern of a juvenile Christmas wrasse will change completely once it matures into an adult. Mature females will sport a more drab red-and-green pattern while males are more vibrant and have more intricate patterns.
Christmas wrasse live in harems led by a single brilliantly colored male and his alpha female. If the harem loses its reigning male, the alpha female will change herself into a male in every way. This transformation from the initial to the terminal phase is a one-time transformation.
The changes were noticed by Hawaiians who had different names for the fish that were in various color phases. This process was documented in the published works of the Frenchman credited with discovering this fish 212 years ago, Bernard Germain de Lacepede.
He wrote: "The species can undergo such a large number of modifications in its forms and qualities, that without losing its vital capacity, it may be, by its latest conformation and properties, farther removed from its original state than from a different species: it is in that case metamorphosed into a new species."
This drastic transformation led scientists to believe that the different sexes were actually different species! For many years males and females had different scientific names as though they were completely different species.
These carnivorous fish can grow to about 11 inches and primarily live in very shallow waters in the coral reef, hunting small crabs and other invertebrates. Hawaii, being the most remote island chain in the world and in the middle of the Pacific Ocean, receives a constant pounding from large oceanic swells.
This area of the coastline is known as the surge zone, but the Christmas wrasse is a fast fish and can easily navigate the rough reef topography. Hopefully with some keen observation and caution, you will be gifted with a glimpse of the most festive fish prancing around the reef this Christmas season.
* Erin Iberg is the Maui Ocean Center's community education manager. "Ka Mo'olelo Moana," or "The Ocean Story," is a monthly column submitted by the center. It is open 9 a.m. to 5 p.m. daily in Maalaea. For more information, call 270-7000.