---
title: Red Sea Longnose Filefish (Oxymonacanthus halli)
scientific_name: Oxymonacanthus halli
common_name: Red Sea Longnose Filefish
taxon: Filefishes
conservation_status: VU - Vulnerable
published: 2024-11-24T19:54:55.115Z
updated: 2025-11-25T13:58:09.000Z
tags: Red Sea Longnose Filefish, Oxymonacanthus halli, Filefishes, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/fishes/bony-fishes/filefishes/red-sea-longnose-filefish
---

# Red Sea Longnose Filefish (*Oxymonacanthus halli*)

**Taxon:** Filefishes (*Monacanthidae*)  
**Conservation Status:** VU - Vulnerable  


The Red Sea Longnose Filefish, also known as the Harlequin Filefish (scientific name: Oxymonacanthus halli), is a distinctive fish found in the tropical marine waters of the Western Indian Ocean, particularly the Red Sea. This species thrives in coral-rich environments, inhabiting fringing reefs at shallow depths ranging from 1 to 10 meters (approximately 3 to 33 feet).

The maximum length the Red Sea Longnose Filefish can reach is about 7 centimeters (roughly 2.8 inches). These fish are typically seen in pairs but can occasionally be found in small groups. Their diet primarily consists of Acropora polyps, a type of coral.

This species exhibits a fascinating form of camouflage by mimicking the appearance of Acropora coral. Its body is adorned with rows of yellow spots on its sides, allowing it to blend seamlessly with its coral surroundings.

The name 'Oxymonacanthus' is derived from Greek, where 'oxys' means sharp, 'monos' means one, and 'akantha' refers to thorn, reflecting the sharp, singular thorn-like structures associated with these fish.

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/fishes/bony-fishes/filefishes/red-sea-longnose-filefish)*
*Updated: November 25, 2025*