Moon Wrasse

Interesting Info

• The Moon Wrasse is a colourful reef fish found widely across northern Australia from Western Australia through the Northern Territory to Queensland, reaching into northern New South Wales. Globally, it is common throughout the Indo-Pacific from East Africa and the Red Sea to Japan, Samoa, and New Caledonia.
• The body is typically greenish-blue with a bright crescent-shaped yellow-green patch on the sides, which gives the species its name. The head is darker blue with a pointed snout, and males often have extended fins and more intense rainbow-like colours.
• Juveniles look very different to adults, usually dark blue to black with small electric-blue spots. This striking contrast means they can easily be mistaken for a different species until they mature.
• Like many wrasses, they are protogynous hermaphrodites, starting life as females before some change into dominant, brightly coloured males.
• They are active carnivores that feed on crabs, shrimps, snails, worms, brittle stars, and even small bony fishes, using their sharp teeth to pry prey from reef crevices.
• Moon Wrasses are very active by day, often seen in small groups or loose schools that move quickly across reef slopes and flats while foraging.
• Juveniles are known to act as cleaner fish, picking parasites from larger reef fishes. Adults may still clean occasionally but mostly switch to hunting invertebrates.
• During courtship, males brighten dramatically, chase females, and perform rapid displays before spawning together in the water column. Fertilised eggs drift freely with the currents until they hatch.
• Unlike some male wrasse, the Moon Wrasse does not guard eggs; wrasse eggs are left to drift and develop independently.
• They are fast and agile swimmers capable of sudden bursts of speed, helping them both capture prey and evade larger predators like groupers, trevallies, and moray eels.
• At night, Moon Wrasses wedge themselves into coral or rubble crevices, often changing to a duller colour to avoid detection while resting.
• They typically live up to 10 years in the wild.
• Divers and snorkellers recognise them instantly by their crescent-shaped side patch, and their constant activity makes them one of the most visible wrasses on Indo-Pacific reefs.