Spot-nape butterflyfish (Chaetodon oxycephalus)

Classification (WoRMS)

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

Accepted name: Chaetodon oxycephalus · Authority: Bleeker, 1853 · Taxonomic status: accepted · AphiaID: 218725.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218725 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 25 cm · Depth range: 10–40 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 15 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Found in coral-rich areas of coastal reefs, feeding mainly on coral polyps and anemones (Ref. 9710). Occurs solitarily or in pairs (Ref. 90102). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).

Source: FishBase species summary (SpecCode 5472) — https://www.fishbase.se/summary/Chaetodon-oxycephalus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

233 georeferenced occurrence records for Chaetodon oxycephalus are published through GBIF from 14 countries or marine areas. The map above plots 89 distinct locations from a sample of 233 records, omitting 7 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: Indonesia (76); Fiji (34); Australia (30); Philippines (24); Palau (15); Papua New Guinea (14); Maldives (13); Solomon Islands (13); Vanuatu (6); India (2); Malaysia (2); Seychelles (2); Tonga (1); United States of America (1).

Marine regions with a valid WoRMS distribution record: Chagos.

Source: GBIF Occurrence Search (taxonKey 2385550) — https://www.gbif.org/occurrence/search?taxon_key=2385550&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218725 (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 oxycephalus Bleeker, 1853 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 165664) — https://www.iucnredlist.org/species/165664/0; GBIF IUCN Red List category endpoint (taxonKey 2385550) — https://api.gbif.org/v1/species/2385550/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The specific name of the spot-nape butterflyfish is formed by combining oxy, meaning "sharp" (the oxy part of "oxygen" is also taken from here), and cephalus, meaning "head". Bleeker used this term to refer to the pointed profile of the projecting snout of this species.

Within its genus, the spot-nape butterflyfish belongs to the large subgenus Rabdophorus, which might warrant recognition as a distinct genus. Molecular phylogenetic studies indicate that, in this group, this butterflyfish belongs to a clade also containing the black-wedged vutterflyfish (C. falcula), the Pacific double-saddle butterflyfish (C. ulietensis), the lined butterflyfish (C. lineolatus) and the blue-cheeked butterflyfish (C. semilarvatus). However, there is not yet a consensus regarding the internal relationships among these species.

The flanks of the spot-nape butterflyfish are mostly white, overlaid with thin vertical lines. There is a large yellow-margined black area on the upper back, which touches the dorsal, anal and caudal fins. All these fins are mostly yellow, but there are some black and orange lines and spots on them as well. There is also a vertical black eyestripe, which is interrupted above the eyes. The closely related lined butterflyfish has a very similar appearance, but there are still noticeable differences, as the latter lacks the black and orange elements in the fins and has an uninterrupted black eyestripe.

The spot-nape butterflyfish is found in the Indo-West Pacific region, from Sri Lanka in the west to Queensland in the south and Indonesia and the Philippines in the north. It occurs in coral-rich areas and clear waters of seaward reefs at depths of 10-40 m.

The spot-nape butterflyfish feeds on coral polyps and sea anemones.

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