Bluecheek butterflyfish (Chaetodon semilarvatus)

Classification (WoRMS)

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

Accepted name: Chaetodon semilarvatus · Authority: Cuvier, 1831 · Taxonomic status: accepted · AphiaID: 218742.

Synonyms and superseded combinations recorded for this taxon: Chaetodon melanopoma Playfair, 1867.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218742 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 23 cm · Common length: 15 cm · Depth range: 3–20 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 16.7 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: A common species (Ref. 9710) found in areas where there is rich coral growth. Often seen in pairs or small aggregations. Occasionally observed hovering in a stationary position for extended periods under ledges of Acropora plate corals (Ref. 4858). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).

Source: FishBase species summary (SpecCode 12300) — https://www.fishbase.se/summary/Chaetodon-semilarvatus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

981 georeferenced occurrence records for Chaetodon semilarvatus are published through GBIF from 9 countries or marine areas. The map above plots 52 distinct locations from a sample of 981 records, omitting 6 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: Egypt (882); Saudi Arabia (76); Djibouti (8); Sudan (4); Eritrea (3); Israel (3); Yemen (3); Germany (1); Oman (1).

Marine regions with a valid WoRMS distribution record: Eritrean Exclusive Economic Zone; Somali Exclusive Economic Zone; Red Sea; Djiboutian Exclusive Economic Zone.

Source: GBIF Occurrence Search (taxonKey 2385470) — https://www.gbif.org/occurrence/search?taxon_key=2385470&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=218742 (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 semilarvatus Cuvier, 1831 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 165670) — https://www.iucnredlist.org/species/165670/0; GBIF IUCN Red List category endpoint (taxonKey 2385470) — https://api.gbif.org/v1/species/2385470/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The bluecheek butterflyfish has a bright yellow body marked with thin vertical red lines. There a greyish patch behind the eyes, whereas most related species have an eye bar. The dorsal, anal, pelvic and caudal fins are yellow. It is a relatively large species of butterflyfish which can attain a maximum total length of 23 cm, although 15 cm is more typical.

The bluecheek butterflyfish is found in the north-western Indian Ocean where it occurs in the Red Sea and the Gulf of Aden, as far east as the coast of Oman.

The bluecheek butterflyfish is one of the few fish species to have long-term mates. In the wild, the fish eats hard corals as well as benthic invertebrates. This is a common species which is found in areas with rich coral growth. They are frequently recorded in pairs or in small shoals. They have been known to occasionally hover in a stationary position for long periods beneath ledges of plate corals of the genus Acropora. It is oviparous species which forms pairs when spawning. This is normally during the day and the fishes emerge and are active at night. They are found at depths between 1 and 20 m.

The bluecheek butterflyfish was first formally described in 1831 by the French anatomist Georges Cuvier with the type locality given as the Red Sea at Massawa, Eritrea and Al-Luhayya, Yemen. It belongs to the large subgenus Rabdophorus which might warrant recognition as a distinct genus. In this group, it seems closest to a group containing the blackback butterflyfish (C. melannotus), the spot-naped butterflyfish (C. oxycephalus), or the peculiar black-wedged butterflyfish (C. falcula) and Pacific double-saddle butterflyfish or "false falcula", (C. ulietensis). Though the present species does not share their white body with black on the back and caudal peduncle and even lacks the typical eyestripe of Chaetodon, it has the same tell-tale blue vertical lines as these species.

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