The moon wrasse (''Thalassoma lunare'') also known as the crescent wrasse or lyretail wrasse, is a species of

wrasse The wrasses are a family, Labridae, of marine fish, many of which are brightly colored. The family is large and diverse, with over 600 species in 81 genera, which are divided into 9 subgroups or tribes. They are typically small, most of them le ...

native to the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...

and the western

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

. It is an inhabitant of

coral reefs A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Co ...

and surrounding areas at depths from . Moon wrasses are carnivorous and tend to prey on fish eggs and small sea-floor dwelling invertebrates. This species can reach in total length. It is of minor importance to local

commercial fisheries Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often p ...

and can also be found in the aquarium trade. The juvenile is blue on the lower half of its body, with a black spot in the middle of the dorsal fin and a black blotch on the caudal fin base. As it matures, the spot turns into a yellow crescent, hence the name. The body is green, with prominently marked scales. Coloration of the head ranges from blue to magenta, with a broken checkerboard pattern. Moon wrasses are active fish, said to be moving all day long. They are also territorial, nipping, chasing, and otherwise harassing fish that get in their way. Being diurnal, wrasses have strong vision, although they also have a decent sense of smell. At night, they rest in niches often under rocks or other such structures. If needed, a moon wrasse may dig out space under a rock by repeatedly swimming through it until it fits without struggle. They are

protogynous Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...

hermaphrodites, all starting off as females and changing to males, a process which, for the moon wrasse, takes only 10 days. Some moon wrasses live in groups consisted of a dominant male, and a "harem" of about a dozen other wrasses, some female and some male. The alpha male is more brightly colored, and at every low tide hour, changes from green to blue, and goes into a show of attacking and nipping all the other wrasses. During breeding season and before high tide, the alpha male turns completely blue, gathers up every single female, and the spawning frenzy begins. Moon wrasses may live up to a decade in captivity, although this is shorter in the wild. They are popular fish in the aquarium trade, due to their hardiness, bright colors, and engaging behavior. They are renowned for their ability to tolerate spikes in nitrite, and eat

bristle worms Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made ...

, which can be an aquarium pest.

References

http://www.petco.com/product/104902/Lunare-Wrasse.aspx

Bibliography

The New Encyclopedia of the Saltwater Aquarium, Greg Jennings, 2007. The Inspired Aquarium: Ideas and Instructions for Living with Aquariums, Senske, 2006. Under the seas, the Ecology of Australia's Rocky Reefs, Neil Andrew, 2000.

External links

* {{Taxonbar, from=Q947679 Thalassoma Fish of Thailand Fish described in 1758 Taxa named by Carl Linnaeus Labridae