Saint Helena butterflyfish (Chaetodon sanctaehelenae)

Classification (WoRMS)

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

Accepted name: Chaetodon sanctaehelenae · Authority: Günther, 1868 · Taxonomic status: accepted · AphiaID: 273360.

Synonyms and superseded combinations recorded for this taxon: Chaetodon sanctae helenae Günther, 1868; Chaetodon sanctaehelena Günther, 1868; Chaetodon sanctaehelenae uniformis Ahl, 1923.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273360 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 18 cm · Depth range: 0–50 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 10 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Common in shallow waters. Usually observed in pairs or large groups. Oviparous (Ref. 205), monogamous (Ref. 52884).

Form pairs during breeding (Ref. 205). Called a cunning fish since it can nibble the bait from a hook without taking the hook into its mouth. The juvenile Thalassoma sanctaehelenae has been observed cleaning the cunningfish of its parasites (Ref. 5288).

Source: FishBase species summary (SpecCode 12536) — https://www.fishbase.se/summary/Chaetodon-sanctaehelenae.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

99 georeferenced occurrence records for Chaetodon sanctaehelenae are published through GBIF from 2 countries or marine areas. The map above plots 3 distinct locations from a sample of 99 records, omitting 1 inland record 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: Saint Helena, Ascension and Tristan da Cunha (97); Liberia (2).

Source: GBIF Occurrence Search (taxonKey 2385345) — https://www.gbif.org/occurrence/search?taxon_key=2385345&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273360 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-25.

Conservation status (IUCN Red List)

The IUCN Red List assesses Chaetodon sanctaehelenae Günther, 1868 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 165715) — https://www.iucnredlist.org/species/165715/0; GBIF IUCN Red List category endpoint (taxonKey 2385345) — https://api.gbif.org/v1/species/2385345/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

The Saint Helena butterflyfish has a silvery-white body with a vertical black band running through the eye. The caudal peduncle is yellow, as are the dorsal and anal fins. The dorsal fin contains 13 spines and 21-23 soft rays while the anal fin has 3 spines and 19 soft rays. This species attains a maximum total length of 18 cm.

The Saint Helena butterflyfish is found in the southeastern Atlantic Ocean where it is endemic to the waters around the British Overseas Territories of Ascension and Saint Helena islands. Vagrants have reached as far north as Liberia and the Canary Islands.

The Saint Helena butterflyfish is a common species of the shallow waters where it occurs. It is normally recorded in pairs or big shoals. It is an oviparous and monogamous species which forms pairs during spawning. Locally, this species is named cunningfish because it is able to nibble the bait from a hook while avoiding the hook.

The juveniles of Thalassoma sanctaehelenae have been recorded acting as a cleaner fish, picking the parasites off this species. They frequently gather in shoals to feed on refuse tipped into the Saint Helena harbour. Normally they feed on benthic invertebrates.

The Saint Helena butterflyfish was first formally described 1868 by the German-born British zoologist Albert Günther (1830-1914). Some authorities place this species within the subgenus Exornator but others consider it to be incertae sedis.

Source: Wikipedia: Saint Helena butterflyfish — https://en.wikipedia.org/wiki/Saint_Helena_butterflyfish (CC BY-SA 4.0). Accessed 2026-09-25.