Harlequin Filefish
Oxymonacanthus longirostris
A charismatic, although infrequently encountered, fish with a striking colour pattern of bright yellow-orange spots on a blue-green background. Fins mostly yellowish except for the blackish pelvic fin rudiment and a black spot on the caudal fin.
Morphology
The shallow body depth, elongated snout and vivid colour pattern (described above) make this species unmistakable. Grows to a maximum size of 12 cm.
Evolution
Only two species are currently known in the genus Oxymonacanthus, which is part of the Family Monacanthidae, a group more commonly known as Leatherjackets or Filefishes. These fishes are so named for their tough, leathery skin which has a sandpaper-like feel due to the presence of a dense covering of tiny spines.
Behaviour
Feeds exclusively on the polyps of Acropora corals, a mode of feeding for which the species has evolved its elongated, tubular snout. Population declines linked to coral bleaching. Lives in monagomous pairs (see reproduction notes below).
Method of reproduction
Sexual; forms exclusive monogamous pairs and spawns amongst dead coral often on algae.
Habitat
Marine
Shallow reefs with Acropora coral growth, between 1-35 m depth.
Distribution
Throughout tropical parts of the Indo-West Pacific region from East Africa to Tonga, including coastal and offshore reefs of north-western Australia and the Great Barrier Reef.
Life Cycle
Oviparous
| Kingdom: | Animalia |
|---|---|
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Tetraodontiformes |
| Family: | Monacanthidae |
| Genus: | Oxymonacanthus |
| Species: | longirostris |
| Name Published Year: | 1801 |
|---|---|
| Scientific Name Authorship: | Bloch & Schneider |
| Commercial Impact: | Highly prized in the aquarium trade, with large numbers removed from the wild annually. |
| Conservation Assessment: | Vulnerable |
Cite this page
Western Australian Museum Collections https://museum.wa.gov.au/online-collections/names/Oxymonacanthus-longirostris
Accessed 28 May 2025
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