The orange spotted filefish or harlequin filefish, is a filefish in the family Monacanthidae found on coral reefs in the Indo-Pacific Oceans.
The orange spotted filefish is pale blue with about eight longitudinal rows of orange-yellow patches.
It grows to 9 cm in length.
Harlequin Filefish use chemical camouflage to hide from predators.
The species is often seen in pairs feeding on coral polyps. The longnose filefish, usually lives in heterosexual pairs, the male and female swimming together and sharing the same territory.
A friendly species with seahorses and pipefish form a good association since they are all slow animals that are hard to reach for food.
Feeds exclusively on Acropora polyps. Feeding takes place throughout the day becoming less towards the evening.
Aggression is used commonly in courtship. Spawning commences when after swimming together in different tufts, the female concentrates on just one and begins to thrust repeatedly and pause. The male follows suit nuzzling the female. The female then drops into the algae and spawns, while the male releases the sperm beside her. The pair then swims back to their territory. Monogamous mating is observed as both facultative and social.
A highly prized aquarium fish.
Because of its dependency on Acropora reefs, O. longirostris is susceptible to population declines due to habitat loss in parts of its range. As of 2008, 15% of the world’s coral reefs were considered under imminent threat of being “Effectively Lost” (with 90% of the corals lost and unlikely to recover soon), with regions in East Africa, South and South-east Asia among the most threatened (Wilkinson and Souter 2008). Of 704 zooxanthellate reef-building coral species which were assessed by using the International Union for Conservation of Nature Red List Criteria, 32.8% are in categories with elevated risk of extinction (Carpenter et al. 2008). Of the 167 Acropora species occurring in the Indo-Pacific, 51 (30%) are listed in a threatened category (Vulnerable or Endangered), and another 23 (13%) are Near Threatened. In 1998, an extensive bleaching event was observed in reef areas worldwide. This event severely impacted the fringing reefs of Bise, off the northwest coast of Okinawa, Japan, with most of the living coral dying and filamentous algae quickly covering the dead corals. Of all species, acroporid corals seemed the most susceptible to bleaching (Hoegh-Guldberg and Salvat 1995, McClanahan 2000).According to a leading expert in aquarium-related fishes, O. longirostris is one of the most difficult ornamental fishes to keep alive in captivity (Michael 1999), yet data from the UNEP World Conservation Monitoring Centre, and the Marine Aquarium Database (GMAD) which was assembled in 2000, indicate O. longirostris is one of, if not the, most heavily traded fishes that have been classified as most unsuitable for maintenance in aquaria (Wabnitz et al. 2003). Reports in the database indicate that 1,393 individuals of Harlequin filefish were traded between the years of 1999-2002, but reports by exporters between the same time period indicate that nearly 16,000 individuals were exported. High collection rates of this fish for the aquarium trade in addition to the higher frequency of natural disaster events such as bleaching observed in recent years may genuinely put at risk local populations and drive stocks below their critical recovery level (Kokita and Nakazono 1999, Kokita and Nakazono 2001).