Dotted butterflyfish (Chaetodon semeion)

Classification (WoRMS)

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

Accepted name: Chaetodon semeion · Authority: Bleeker, 1855 · Taxonomic status: accepted · AphiaID: 273361.

Synonyms and superseded combinations recorded for this taxon: Chaetodon decoratus Ahl, 1923; Chaetodon semion Bleeker, 1855.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273361 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 26 cm · Depth range: 0–50 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 16 of 100 · Fishery importance: minor commercial · Aquarium trade: commercial.

FishBase notes: Uncommon species (Ref. 9710) found in coral rich areas of clear water lagoon and semi-protected seaward reefs. Usually in pairs or small groups, more wary than most species. Minimum depth reported taken from Ref. 30874. Oviparous (Ref. 205). Minimum depth reported taken from Ref. 128797.

Source: FishBase species summary (SpecCode 5575) — https://www.fishbase.se/summary/Chaetodon-semeion.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

770 georeferenced occurrence records for Chaetodon semeion are published through GBIF from 25 countries or marine areas. The map above plots 158 distinct locations from a sample of 770 records, omitting 12 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: Palau (109); American Samoa (101); Wallis and Futuna (93); Indonesia (85); Australia (77); Papua New Guinea (53); Solomon Islands (46); Marshall Islands (35); Fiji (21); Guam (20); Micronesia (Federated States of) (19); Tonga (15); Tuvalu (15); New Caledonia (14); Samoa (12).

Source: GBIF Occurrence Search (taxonKey 2385329) — https://www.gbif.org/occurrence/search?taxon_key=2385329&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273361 (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 semeion Bleeker, 1855 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 165725) — https://www.iucnredlist.org/species/165725/0; GBIF IUCN Red List category endpoint (taxonKey 2385329) — https://api.gbif.org/v1/species/2385329/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The dotted butterflyfish is a bright golden yellow colour with a vertical, teardrop shaped bar running through the eye. It has a blue forehead and there are slightly oblique rows of black spots along their flanks. The dorsal, anal, pectoral and pelvic fins are yellow, with the bases of the dorsal and anal fins coloured black, and a filament growing out of the soft rayed part of the dorsal fin. Females have a notably thickened abdominal region. This species has 13-14 spines and 23-26 soft rays in its dorsal fin, while the anal fin has 3 spines and 19-22 soft rays. They attain a maximum total length of 26 cm.

The dotted butterflyfish is found in the Indian Ocean and Pacific Ocean from the Maldives to the Tuamotu Islands, north to the Ryukyu Islands and south to the Great Barrier Reef.

The dotted butterflyfish is found at depths between 2 and 30 m. It is an uncommon species which occurs in coral rich areas of clear water such as lagoons and semi-protected seaward reefs, it is usually found in pairs or small groups and more wary than most species of Chaetodon. They are an oviparous species. This species feeds on tunicates and other ascidians, and a variety of benthic invertebrates.

The dotted butterflyfish was first formally described in 1855 by the Dutch physician, ichthyologist and herpetologist Pieter Bleeker (1819-1878) with the type locality being given as Cocos (Keeling) Islands, an Australian Indian Ocean territory. The specific name semeion means "banner" and is thought to be a reference to the long dorsal fin filament. This species belongs to the large subgenus Rabdophorus which might warrant recognition as a distinct genus. In this group, it appears to represent a distinct lineage, with the saddle butterflyfish (C. ephippium) perhaps the only somewhat closely related species. Next closest seems to be a group including the blackback butterflyfish (C. melannotus), spot-tailed butterflyfish (C. ocellicaudus) and yellow-dotted butterflyfish (C. selene), but these are already so distant that their ancestors must have diverged from the saddle butterflyfish's soon after the Rabdophorus lineage started to diversify.

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