False moorish idol (Heniochus diphreutes)

Classification (WoRMS)

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

Accepted name: Heniochus diphreutes · Authority: Jordan, 1903 · Taxonomic status: accepted · AphiaID: 218763.

Synonyms and superseded combinations recorded for this taxon: Heniochus diphreustes Jordan, 1903.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218763 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 21 cm · Depth range: 5–210 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 11 of 100 · Fishery importance: of no interest · Aquarium trade: commercial.

FishBase notes: Occur primarily along outer reef slopes, in current channels. Juveniles in aggregations around isolated patch reefs, adults in large schools well above the bottom (Ref. 9710). In Indonesia, adults most common in depth 40-50 m, reported to 200 m (Ref. 48636). Benthopelagic (Ref. 58302). Feed on plankton. Juveniles may act as cleaners (Ref. 9710); also observed in adults (Ref. 48636). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).

Source: FishBase species summary (SpecCode 7769) — https://www.fishbase.se/summary/Heniochus-diphreutes.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

1,967 georeferenced occurrence records for Heniochus diphreutes are published through GBIF from 43 countries or marine areas. The map above plots 284 distinct locations from a sample of 1,967 records, omitting 45 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: Australia (608); United States of America (413); Egypt (173); Indonesia (141); Maldives (127).

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

Source: GBIF Occurrence Search (taxonKey 2385729) — https://www.gbif.org/occurrence/search?taxon_key=2385729&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218763 (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 diphreutes Jordan, 1903 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 165683) — https://www.iucnredlist.org/species/165683/0; GBIF IUCN Red List category endpoint (taxonKey 2385729) — https://api.gbif.org/v1/species/2385729/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The schooling bannerfish is a small fish that can reach a maximum length of 18–21 cm.

Its body is compressed laterally, and the first rays of its dorsal fin stretch in a long white filament. Its background color is white with two large black diagonal bands. Beyond the second black stripe, the dorsal, caudal fins and pectoral fins are yellow. The head is white, the eyes are black and linked together by a black to gray band. The short snout, spotted with black to gray, has a small terminal, extensible mouth.

The schooling bannerfish is widespread throughout the tropical, subtropical and temperate waters of the Indo-Pacific from the eastern coast of Africa, Red Sea included, to Polynesia and Hawaii and from the Great Barrier Reef, to south Japan to the Kermadec Islands (New Zealand).

The schooling bannerfish prefers external reef slopes and channels. It has a large depth range and is usually observed at 5–30 m depth, but may reach 210 meters deep in some localities.

As is indicated by its common name, the schooling bannerfish lives in large groups. It feeds on zooplankton in the open water, and juveniles may act as cleaner fish, and this has also been seen in adults. This oviparous species forms pairs to breed. They have been observed cleaning parasites off the short sunfish (Mola ramsayi) off the Maldives.

In some geographic areas, the schooling bannerfish is harvested for the aquarium trade and is commonly sold as a cheaper alternative to the Moorish idol.

However, there do not appear to be any major current threats to this species, and it is listed as Least Concern by the IUCN.

Source: Wikipedia: Schooling bannerfish — https://en.wikipedia.org/wiki/Schooling_bannerfish (CC BY-SA 4.0). Accessed 2026-09-23.