Threebanded butterflyfish (Chaetodon humeralis)

Classification (WoRMS)

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

Accepted name: Chaetodon humeralis · Authority: Günther, 1860 · Taxonomic status: accepted · AphiaID: 273343.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273343 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 25.399999618530273 cm · Common length: 12 cm · Depth range: 3–50 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 15.4 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Usually observed in pairs or small groups in rocky areas near the shore (Ref. 4858). Feed on algae and benthic invertebrates (Ref. 28023). Form schools with Chaetodipterus zonatus (Ref. 9286). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205). Minimum depth reported from Ref. 5227.

Source: FishBase species summary (SpecCode 8278) — https://www.fishbase.se/summary/Chaetodon-humeralis.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

2,503 georeferenced occurrence records for Chaetodon humeralis are published through GBIF from 11 countries or marine areas. The map above plots 136 distinct locations from a sample of 2,503 records, omitting 64 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: Mexico (1,153); Ecuador (565); Costa Rica (320); Panama (230); Colombia (178).

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

Source: GBIF Occurrence Search (taxonKey 2385520) — https://www.gbif.org/occurrence/search?taxon_key=2385520&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273343 (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 humeralis Günther, 1860 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 165635) — https://www.iucnredlist.org/species/165635/0; GBIF IUCN Red List category endpoint (taxonKey 2385520) — https://api.gbif.org/v1/species/2385520/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

Chaetodon humeralis was first formally described in 1860 by the German-born British zoologist Albert Günther (1830–1914) with the type locality given as "the Sandwich Islands" in error for Central America. Some authorities place this species within the nominate subgenus Chaetodon but others consider it to be incertae sedis.

Chaetodon humeralis is found in the Eastern Pacific Ocean, its most northerly occurrence is at Redondo Beach in Los Angeles, California and from there, its range extends south to Peru. It is also found around the Galapagos Islands of Ecuador, the Revillagigedo Islands of Mexico, Cocos Island in Costa Rica and Malpelo Island in Colombia.

Chaetodon humeralis has an oval disc-like body which is strongly compressed and it has a small mouth positioned at the end of a short snout. The colour of the body is white or silvery white with obvious brownish-black bands on the line of the pectoral fin and another running in from the base of the caudal fin, a third brownish-black band runs from the nape down through the eye to the throat. The median fins all have black bands through them. There are 12–13 spines and 18–20 soft rays in the dorsal fin while the anal fin contains 3 spines and 15–17 soft rays. The maximum total length reached is 25.4 cm but 12 cm is more typical.

Chaetodon humeralis is strongly associated with rock reefs but has been recorded over a variety of substrates in different parts of its range, including intertidal pools, mangroves and estuaries. It is normally encountered in pairs or small shoals, often near the shore. It will mix in shoals with the Pacific spadefish (Chaetodipterus zonatus). It forms pairs to spawn, laying pelagic eggs. It feeds on benthic invertebrates and algae. it has a depth range of 2 to 55 m but is more common between 3 and 12 m.

Source: Wikipedia: Chaetodon humeralis — https://en.wikipedia.org/wiki/Chaetodon_humeralis (CC BY-SA 4.0). Accessed 2026-09-23.