Masked bannerfish (Heniochus monoceros)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Acanthuriformes · Family: Chaetodontidae · Genus: Heniochus.

Accepted name: Heniochus monoceros · Authority: Cuvier, 1831 · Taxonomic status: accepted · AphiaID: 218764.

Synonyms and superseded combinations recorded for this taxon: Heniochus monoceras Cuvier, 1831; Taurichthys monoceros (Cuvier, 1831).

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218764 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

Measured values published by FishBase for Heniochus monoceros. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 24 cm · Depth range: 2–30 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 14 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Occur in lagoon and seaward reefs with rich coral growth. Juveniles solitary; adults are often paired and occasionally found hovering side by side under tabular corals (Ref. 1602). Feed on bottom living animals (Ref. 6113), e.g. invertebrates associated with algal zones (Ref. 5503). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205). Minimum depth reported taken from Ref. 30874.

Source: FishBase species summary (SpecCode 5590) — https://www.fishbase.se/summary/Heniochus-monoceros.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

2,080 georeferenced occurrence records for Heniochus monoceros are published through GBIF from 50 countries or marine areas. The map above plots 311 distinct locations from a sample of 2,080 records, omitting 26 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: New Caledonia (287); Australia (204); Réunion (198); American Samoa (147); French Polynesia (143).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2385719) — https://www.gbif.org/occurrence/search?taxon_key=2385719&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218764 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Conservation status (IUCN Red List)

The IUCN Red List assesses Heniochus monoceros Cuvier, 1831 as Least Concern (code LC). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.

Source: IUCN Red List of Threatened Species (taxon 165650) — https://www.iucnredlist.org/species/165650/0; GBIF IUCN Red List category endpoint (taxonKey 2385719) — https://api.gbif.org/v1/species/2385719/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The masked bannerfish is a small-sized fish that can reach a maximum length of 23 cm.

Its body is compressed laterally, the first rays of its dorsal fin stretch in a white filament outlined with yellow.

The background body color is white with two black vertical bands. The first band masks its face starting at its mouth, and runs to the base of the first rays of the dorsal fin including at the same time its snout and eyes. The lips are white and a fin whitish band runs between the eyes and another one occurs on top of the eyes.

the masked bannerfish has a small growth on the axis of the forehead from which radiates a bright whitish to yellowish area.

The second band is right in the middle of the fish side.

A yellow area extends from the posterior edge of the second black band to the middle of the anal fin including on the way the dorsal and caudal fins. Within this yellow area close to the caudal peduncle, a brown-yellow blotch, variable in size from one fish to another, emerges.

The masked bannerfish is widespread throughout the tropical and subtropical waters of the Indo-Pacific area from the eastern coast of Africa to Polynesia and from south Japan to New-Caledonia).

The masked bannerfish typically lives in external reef slopes and in lagoon rich in corals, at a depth of 2 - 30 m.

Depending on the geographic area, the masked bannerfish lives in pairs or in groups (i.e. especially along island reefs in the Indian Ocean) but always close by its shelter reef and feeds on benthic invertebrates.

In some geographic area the masked bannerfish is harvested occasionally for the aquarium trade. However, there do not appear to be any current threats to this species and it is listed as Least Concern (LC) by the IUCN.

Source: Wikipedia: Heniochus monoceros — https://en.wikipedia.org/wiki/Heniochus_monoceros (CC BY-SA 4.0). Accessed 2026-09-23.