---
title: Unicorn Filefish (Aluterus monoceros)
scientific_name: Aluterus monoceros
common_name: Unicorn Filefish
taxon: Filefishes
conservation_status: DD - Data Deficient
published: 2024-11-24T18:53:45.673Z
updated: 2026-08-13T08:10:37.260Z
tags: Unicorn Filefish, Aluterus monoceros, Filefishes, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/fishes/bony-fishes/filefishes/unicorn-filefish
---

# Unicorn Filefish (*Aluterus monoceros*)

## Quick facts

- **Group:** Filefishes (*Monacanthidae*)
- **Size:** up to 76 cm
- **Weight:** 2.7 Kg
- **Depth:** 1-80 m
- **Diet:** Omnivore
- **Activity:** Diurnal
- **Rarity:** Rare
- **Habitat:** Open water and deep sand, juveniles under drifting weed
- **Reproduction:** Broadcast spawner, Gonochoric
- **Hazard:** Poisonous
- **Conservation status:** DD - Data Deficient

## How to recognise it

- tall flattened gray-brown body with no pattern to speak of
- single long spine above the eye, raised and locked when alarmed
- small pointed mouth and a rounded tail, fins nearly transparent
- length up to 76 cm

A tall, flattened, plain gray-brown fish to 76 cm (30 in) with a single long spine over the eye and almost no markings. The plainness is the identification: the other big filefish here is scrawled with blue lines, and this one is not.

The spine is the file of the name and the trigger of its relatives. It locks upright and can only be released by a smaller spine behind it, so a fish jammed into a crevice cannot be extracted - the same lock the triggerfishes use, in a family that mostly does not live in crevices at all.

Unlike the reef filefishes it spends much of its life in open water, drifting with the current and grazing on whatever floats: jellyfish, salps, algae, small crustaceans. Juveniles live under drifting weed far offshore, which is where the young of most open-ocean fish spend their first months.

It is fished heavily in Asia and turns up in surimi and dried fish products, and large individuals have caused ciguatera poisoning - unusual for a fish this far down the food chain, and a reminder that the toxin travels by way of what an animal grazes as well as what it hunts.

## Also known as

- **English:** leatherjacket, unicorn filefish, unicorn leatherjacket
- **French:** Bourse licorne, Bourse loulou
- **Italian:** Pesce lima unicorno
- **German:** Einhorn-Feilenfisch
- **Spanish:** lija barbuda, Puerco de altura, Cachúa
- **Portuguese:** Cangulo-papel, Peixe-porco, Peixe-porco-unicórnio
- **Dutch:** Vijlvis
- **Czech:** pilníkotrn jednotrnný
- **Japanese:** ウスバハギ, Usubahagi
- **Chinese:** 一角剝, 光復魚, 剝皮魚
- **Russian:** Однорогий спинорог, Алутера
- **AF:** Platvis
- **CA:** Peix llima unicorn
- **DA:** Enhjørning-filfisk
- **ID:** Ikan Sukang
- **KO:** 객주리
- **MSA:** Kerosok padi
- **SOM:** Kiin-koy
- **SW:** Kikande
- **TGL:** Papakol, Tiwarik
- **TH:** ปลางัวหางตัด

## Scientific synonyms

- *Aluetera monocerus* (Linnaeus, 1758)
- *Alutarius amphacanthoides* Bleeker, 1851
- *Alutarius macracanthus* Bleeker, 1851
- *Alutera cinerea* Temminck & Schlegel, 1850
- *Alutera guntheriana* Poey, 1863
- *Alutera monocera* (Linnaeus, 1758)
- *Alutera monoceros* (Linnaeus, 1758)
- *Aluteres berardi* Lesson, 1831
- *Aluterus anginosus* Hollard, 1855
- *Balistes monoceros* Linnaeus, 1758
- *Balistes serraticornis* Fréminville, 1813
- *Monacanthus anginosus* Hollard, 1853

## Range

Federal Republic of Somalia, Gulf of Mexico, Mozambique, New Zealand, North Atlantic Ocean, North Pacific Ocean, Seychelles, South Africa

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/fishes/bony-fishes/filefishes/unicorn-filefish)*
*Updated: August 13, 2026*