Millet butterflyfish (Chaetodon miliaris)

Classification (WoRMS)

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

Accepted name: Chaetodon miliaris · Authority: Quoy & Gaimard, 1825 · Taxonomic status: accepted · AphiaID: 218745.

Synonyms and superseded combinations recorded for this taxon: Chaetodon mantelliger Jenkins, 1901; Heterochaetodon burgessius miliaris (Quoy & Gaimard, 1825).

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218745 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 13 cm · Depth range: 0–250 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 12.4 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Inhabit shallow reef flats (Ref. 205). Benthopelagic (Ref. 58302). Form schools at midwater to feed on plankton and benthic invertebrates. Also on shallow seamounts. Oviparous. Form pairs during breeding (Ref. 205).

Source: FishBase species summary (SpecCode 5136) — https://www.fishbase.se/summary/Chaetodon-miliaris.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

3,965 georeferenced occurrence records for Chaetodon miliaris are published through GBIF from 9 countries or marine areas. The map above plots 32 distinct locations from a sample of 3,000 records, omitting 10 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: United States of America (3,804); United States Minor Outlying Islands (154); Australia (1); Egypt (1); Indonesia (1).

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

Source: GBIF Occurrence Search (taxonKey 2385356) — https://www.gbif.org/occurrence/search?taxon_key=2385356&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218745 (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 Chaetodon miliaris Quoy & Gaimard, 1825 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 165721) — https://www.iucnredlist.org/species/165721/0; GBIF IUCN Red List category endpoint (taxonKey 2385356) — https://api.gbif.org/v1/species/2385356/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

In its subgenus Exornator, it probably belongs to a group that also includes the African butterflyfish (C. dolosus), the crochet butterflyfish (C. guentheri) and the reef butterflyfish (C. sedentarius). The crochet butterflyfish might be the closest living relative of C. miliaris. If the genus Chaetodon is split up, Exornator might become a subgenus of Lepidochaetodon.

The millet butterflyfish grows to a maximum length of 13 cm. It is a deep-bodied, laterally flattened fish. The dorsal fin has 13 to 14 spines and 20 to 23 soft rays and the anal fin has 2 to 3 spines and 17 to 20 soft rays. The general body colour is whitish or yellow, with a number of vertical rows of dark spots on the flanks. A broad black stripe runs from above the eye to the base of the operculum, and there is a large black patch on the caudal peduncle.

This fish is endemic to the Hawaiian Islands and the Johnston Atoll, and is found down to depths of at least 250 m. Its habitats include coastal fringing reefs, outer reefs and lagoons.

The millet butterflyfish is a schooling species found in mid-water that feeds on zooplankton. It also feeds opportunistically on polychaete worms and other small invertebrates on the seabed. Food is drawn into the mouth by rapid suction. It does not seem to be territorial but forms aggregations to feed at particular sites on the reef. Although its breeding habits are unknown, the gonads are large as compared with the body size, suggesting that it may have a promiscuous mating system. Breeding takes place between January and May, and newly settled juveniles are found in inner reef areas between April and June.

This butterflyfish is sometimes collected from the wild for the aquarium trade. Its feeding habits make it more suitable for keeping in a reef aquarium than more specialist butterflyfish species that feed on scleractinian corals. Although rare at Johnston Atoll, it is plentiful around the Hawaiian Islands. The International Union for Conservation of Nature believes that the population is stable and that collection has little impact, and they assess the conservation status of this fish as being of "least concern".

Source: Wikipedia: Millet butterflyfish — https://en.wikipedia.org/wiki/Millet_butterflyfish (CC BY-SA 4.0). Accessed 2026-09-23.