Eastern triangle butterflyfish (Chaetodon baronessa)
Source-cited species reference: taxonomy from WoRMS, biology from FishBase, occurrence map from GBIF, conservation from IUCN Red List, description from Wikipedia.
The eastern triangle butterflyfish (Chaetodon baronessa), also known as the baroness butterflyfish, is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae. It is found in the central Indo-West Pacific region from the Cocos-Keeling Islands and Indonesia in the eastern Indian Ocean to Fiji and Tonga, north to southern Japan, south to New Caledonia and New South Wales in Australia.
- Scientific name
- Chaetodon baronessa
- Authority
- Cuvier, 1829
- Family
- Chaetodontidae
- Order
- Acanthuriformes
- Maximum length
- 16 cm
- Depth range
- 5–20 m
- Habitat zone
- reef-associated
- Iucn red list
- Least Concern
- Gbif occurrence records
- 5,003
Classification (WoRMS)
Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Acanthuriformes · Family: Chaetodontidae · Genus: Chaetodon.
Accepted name: Chaetodon baronessa · Authority: Cuvier, 1829 · Taxonomic status: accepted · AphiaID: 273328.
Synonyms and superseded combinations recorded for this taxon: Chaetodon barronessa Cuvier, 1829; Citharoedus gonochaetodon baronessa (Cuvier, 1829).
Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273328 (CC BY 4.0). Accessed 2026-09-23.
Biology and life history (FishBase)
Measured values published by FishBase for Chaetodon baronessa. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.
Maximum length: 16 cm · Depth range: 5–20 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 13.8 of 100 · Fishery importance: commercial · Aquarium trade: commercial.
FishBase notes: Occurs in lagoon and seaward reefs. Feeds exclusively on the polyps of the tubular Acropora corals. Swims in pairs and are territorial. Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).
Source: FishBase species summary (SpecCode 5558) — https://www.fishbase.se/summary/Chaetodon-baronessa.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.
Distribution and occurrence records (GBIF)
5,003 georeferenced occurrence records for Chaetodon baronessa are published through GBIF from 27 countries or marine areas. The map above plots 242 distinct locations from a sample of 3,000 records, omitting 37 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 (2,929); Indonesia (435); Philippines (390); Fiji (349); Solomon Islands (240).
The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.
Source: GBIF Occurrence Search (taxonKey 2385322) — https://www.gbif.org/occurrence/search?taxon_key=2385322&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273328 (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 baronessa Cuvier, 1829 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 165692) — https://www.iucnredlist.org/species/165692/0; GBIF IUCN Red List category endpoint (taxonKey 2385322) — https://api.gbif.org/v1/species/2385322/iucnRedListCategory. Accessed 2026-09-23.
Description and natural history (Wikipedia)
It grows to a maximum of 16 cm long. The body has a pattern of alternating cream and grey-brown to purple chevron-shaped bars. There are three dark bars on the head, including one running across the eye.
The eastern triangle butterflyfish is found in seaward and lagoon coral reefs. They usually swim around in pairs and are territorial. This species feeds exclusively on the polyps of the tubular Acropora corals.
The triangle butterflyfish (C. triangulum) is its western sister species, replacing C. baronessa in the Indian Ocean. The triangle butterflyfishes and the hooded butterflyfish (C. larvatus) form the subgenus Gonochaetodon. If Chaetodon is split up as some researchers propose, this group might go into Megaprotodon as other high-backed and square-bodied species, but its exact relationships are still not well known.
Source: Wikipedia: Eastern triangle butterflyfish — https://en.wikipedia.org/wiki/Eastern_triangle_butterflyfish (CC BY-SA 4.0). Accessed 2026-09-23.
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