Common name: Harlequin filefish

General information

The Harlequin Filefish, scientifically known as Oxymonacanthus longirostris, is a captivating species known for its intricate patterns and elongated snout. This species is a member of the Monacanthidae family and is highly appreciated by aquarists for its unique appearance and behavior. The Harlequin Filefish exhibits a vibrant coloration with a base of light green to yellow, adorned with a multitude of blue to orange spots.

In the wild, these fish are often found in pairs or small groups, and they have a specialized diet that primarily consists of Acropora polyps, which makes them a challenging species to keep in captivity. Their reliance on live coral as a food source is a notable aspect of their ecology and has implications for their care in reef aquariums.

Care

The Harlequin Filefish requires a well-established reef tank with a generous growth of live Acropora corals to thrive, as they are obligate corallivores. Their diet is difficult to replicate in captivity, and attempts to transition them to alternative foods are often unsuccessful. Therefore, they are recommended for experienced aquarists who can provide the necessary dietary needs.

These fish are generally peaceful but can be territorial towards conspecifics and similar-looking species. They need ample hiding places and a mature aquarium with stable water conditions to reduce stress and promote natural feeding behaviors.

Reproduction

Harlequin Filefish are monogamous and form strong pair bonds. In the wild, they engage in elaborate courtship displays and lay their eggs on substrates, often within the branches of Acropora corals. The male guards the eggs until they hatch. Breeding them in captivity is challenging due to their specific habitat and dietary requirements.

Symbiosis

While not involved in symbiosis like clownfish with anemones, the Harlequin Filefish's specialized feeding on Acropora polyps represents a unique ecological interaction. This obligate relationship underscores the importance of preserving their natural coral habitat, both in the wild and within reef aquariums.

Habitat

Oxymonacanthus longirostris is native to the Indo-Pacific region, where it inhabits shallow coral reefs rich in Acropora corals. They are typically found at depths ranging from the surface to about 25 meters, often in lagoons or along reef slopes.