Redtail butterflyfish (Chaetodon collare)

Classification (WoRMS)

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

Accepted name: Chaetodon collare · Authority: Bloch, 1787 · Taxonomic status: accepted · AphiaID: 273330.

Synonyms and superseded combinations recorded for this taxon: Chaetodon collare duplicicollis Ahl, 1923; Chaetodon collaris Bloch, 1787; Chaetodon fowleri Klausewitz, 1955; Chaetodon parallelus Gronow, 1854; Chaetodon praetextatus Cantor, 1849; Chaetodon viridis Bleeker, 1845; Chaetodontops collare (Bloch, 1787).

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273330 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

Maximum length: 18 cm · Depth range: 1–20 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 10 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Occur in coral reefs in pairs or several aggregations. Juveniles in estuaries (Ref. 48636). Commonly exported to Europe and America, but quite difficult to acclimate to aquarium conditions. Feed on coral polyps. Usually found on reef edge and upper slope (Ref. 6113). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).

Source: FishBase species summary (SpecCode 7803) — https://www.fishbase.se/summary/Chaetodon-collare.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

692 georeferenced occurrence records for Chaetodon collare are published through GBIF from 16 countries or marine areas. The map above plots 86 distinct locations from a sample of 692 records, omitting 17 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: Maldives (185); Thailand (173); India (144); Oman (90); Indonesia (37); Sri Lanka (24); Yemen (14); Japan (5); Philippines (5); Australia (4); Myanmar (3); Malaysia (3); Chinese Taipei (2); Christmas Island (1); Fiji (1).

Source: GBIF Occurrence Search (taxonKey 2385374) — https://www.gbif.org/occurrence/search?taxon_key=2385374&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273330 (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 collare Bloch, 1787 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 165723) — https://www.iucnredlist.org/species/165723/0; GBIF IUCN Red List category endpoint (taxonKey 2385374) — https://api.gbif.org/v1/species/2385374/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

It can be found in reefs of the Indo-west Pacific region: from the Persian Gulf and Maldives to Japan, the Philippines, and Indonesia. It usually swims at depths of between 3 and 15 m.

It can grow to 18 cm (over 7 in) in length. The red-tailed butterflyfish is brown to black, with lighter scales giving it a spotted appearance. It has a prominent, vertical white streak behind the eyes, a dark stripe over the eyes, and another, smaller white stripe in front of the eyes. The base of the tail is bright red, followed by a black stripe. The tip of the tail is diffuse white.

In the wild, its diet consists of coral polyps. In captivity, it is a carnivore, taking fish meat and shrimp.

It belongs to the large subgenus Rabdophorus which might warrant recognition as a distinct genus. In this group, its relationships are doubtful; it seems related to the "raccoon-masked" group including the black butterflyfish (C. flavirostris), diagonal butterflyfish (C. fasciatus), Philippine butterflyfish (C. adiergastos) and the raccoon butterflyfish (C. lunula). Its color and pattern is entirely different from these, but it shares the robust habitus and bold habits.

The mailed butterflyfish (C. reticulatus) is a near-match of C. collare in appearance, save for a less brown hue and light blue instead of red in its black-based tail. These two are widely sympatric in the western Pacific. However DNA sequence and osteology data overwhelmingly agree that C. reticulatus belongs to the subgenus called "Citharoedus" (a name preoccupied by a mollusc genus). This contains fish like the scrawled butterflyfish (C. meyeri), similar in shape and size but with a "finger-painted" pattern of a few prominent and uneven lines on a light silvery background.

If Rabdophorus were to be considered a distinct genus, "Citharoedus" would not be included in it but placed with the subgenera Lepidochaetodon or Megaprotodon. Thus, the red-tailed and mailed butterflyfishes probably represent a case of convergent evolution and perhaps mimicry. What selection forces were responsible for the striking similarity between two rather unrelated Chaetodon is not known.

The highly anomalous 12S rRNA mtDNA sequence found in this species in one 2007 study seems to be due to a laboratory error; in another study a 12S rRNA sequence agreeing with the general pattern of mtDNA evolution in Rabdophorus was found.

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