Oneline Wrasse

Interesting Info

• The Oneline Wrasse, also known as the Tubelip Wrasse, is a small reef fish found widely across the tropical Indo-Pacific, including northern Australia, the Great Barrier Reef, Western Australia’s offshore reefs, Lord Howe Island, and the Cocos (Keeling) and Christmas Islands.
• Juveniles are dark brown or black with two bright bluish-white body stripes. As they mature, one of these stripes fades, leaving the distinctive single line that gives the species its common name.
• Females are typically yellowish-brown with faint stripes, while males are brighter with multiple blue lines along the body, a greenish head patterned with blue streaks, and a pale to yellow patch just behind the pectoral fin base.
• They have unusually thick, fleshy yellow lips that form a short tube when closed. This is a specialised feeding adaptation that allows them to feed on coral polyps without being stung.
• Their diet consists almost entirely of coral mucus and soft tissue, especially from branching staghorn corals (Acropora species). This makes them one of the few fish that rely directly on corals for food.
• They are considered mucous-feeders rather than destructive coral biters, meaning they cause little structural damage to coral colonies while still playing a role in reef ecology.
• Like many wrasses, they are believed to be protogynous hermaphrodites, beginning life as females before some transform into dominant, more colourful males.
• Their lifespan has not been precisely documented, but similar small wrasses live around 5–7 years in the wild.
• Divers and snorkellers can often spot them darting among dense coral thickets in shallow lagoons and semi-sheltered reef flats, although they are quick to hide when approached closely.
• They are occasionally collected for the aquarium trade, but their highly specialised coral-based diet makes them nearly impossible to maintain successfully in captivity.
• The species name unilineatus means “one line” in Latin, referring to the distinctive single body stripe of juveniles.