Western talma (Chelmonops curiosus)
Source-cited species reference: taxonomy from WoRMS, biology from FishBase, occurrence map from GBIF, conservation from IUCN Red List, description from Wikipedia.
Chelmonops curiosus, truncate coralfish, truncate butterflyfish, western talma or squareback butterflyfish, is a species of marine ray-finned fish, a butterflyfish from the family Chaetodontidae. It is endemic to Australia.
- Scientific name
- Chelmonops curiosus
- Authority
- Kuiter, 1986
- Family
- Chaetodontidae
- Order
- Acanthuriformes
- Maximum length
- 26 cm
- Depth range
- 51–57 m
- Habitat zone
- reef-associated
- Iucn red list
- Least Concern
- Gbif occurrence records
- 2,745
Classification (WoRMS)
Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Acanthuriformes · Family: Chaetodontidae · Genus: Chelmonops.
Accepted name: Chelmonops curiosus · Authority: Kuiter, 1986 · Taxonomic status: accepted · AphiaID: 280141.
Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=280141 (CC BY 4.0). Accessed 2026-09-23.
Biology and life history (FishBase)
Measured values published by FishBase for Chelmonops curiosus. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.
Maximum length: 26 cm · Depth range: 51–57 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 16 of 100 · Aquarium trade: never/rarely.
FishBase notes: A generally common species found in vertical rock faces. Feed on worms and crustaceans. Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).
Source: FishBase species summary (SpecCode 25434) — https://www.fishbase.se/summary/Chelmonops-curiosus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.
Distribution and occurrence records (GBIF)
2,745 georeferenced occurrence records for Chelmonops curiosus are published through GBIF from 1 countries or marine areas. The map above plots 45 distinct locations from a sample of 2,745 records, omitting 23 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: Australia (2,745).
The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.
Source: GBIF Occurrence Search (taxonKey 2385302) — https://www.gbif.org/occurrence/search?taxon_key=2385302&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=280141 (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 Chelmonops curiosus Kuiter, 1986 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 165706) — https://www.iucnredlist.org/species/165706/0; GBIF IUCN Red List category endpoint (taxonKey 2385302) — https://api.gbif.org/v1/species/2385302/iucnRedListCategory. Accessed 2026-09-23.
Description and natural history (Wikipedia)
Chelmonops curiosus has a very deep strongly compressed body, which is more than half its standard length. It has a small head with a long, tapered snout and a tiny mouth at the end of its snout. There is a single, elongated dorsal fin with the separation between the spiny portion and the soft-rayed portion being hardly visible. The first spine is very small but as they progress towards the posterior they become longer and longer. In juveniles the soft part of the dorsal fin is rounded but it is pointed in adults and has a triangular profile when raised. The anal fin is smaller than the dorsal fin. The caudal fin is truncate. The background colour of this fish is steel grey with amounts of black shading different for each individual. They are marked with 4 vertical black bars with silver edged margins, becoming broader towards the tail. The pelvic fins are black. In juveniles there is an ocellus on the soft part of the dorsal fin which fades as they become mature. The spiny part of the dorsal fin contains 11 spines while the soft part has 25-27 soft rays while the anal fin has 3 spines and 19-20 soft rays. This species attains a maximum total length of 26 cm.
Chelmonops curiosus is endemic to the seas of Australia where it is found along the south coast from Victor Harbor, South Australia and on the western coast as far north as Shark Bay, Western Australia.
Chelmonops curiosus is found on coastal rocky reefs, seeming to prefer vertical rock faces, often where the water is turbid and they will use man-made structures such as pylons and jetties. The juveniles are frequently found swimming among seaweed beds. The adults are normally observed in pairs. This species is omnivorous and its diet comprises small worms, crustaceans, and algae. They breed in pairs. They appear to be territorial, with each pair defending a territory.
Chelmonops curiosus is occasionally collected for the aquarium trade. It is rarely exported from Australia.
Source: Wikipedia: Chelmonops curiosus — https://en.wikipedia.org/wiki/Chelmonops_curiosus (CC BY-SA 4.0). Accessed 2026-09-23.
Frequently Asked Questions
What is Western talma (Chelmonops curiosus)?
Western talma is a deep-water butterflyfish from the family Chaetodontidae, also called truncate coralfish or squareback butterflyfish. It is a ray-finned marine fish found exclusively in Australian waters.
Where does Western talma (Chelmonops curiosus) live and how deep?
This species is endemic to Australia and inhabits reef zones at depths of roughly 51 to 57 meters, well below the typical shallow-reef butterflyfish range. Its restricted, deep-water habitat makes it a rarity in casual diving encounters.
How big does Western talma (Chelmonops curiosus) get?
The truncate butterflyfish reaches a maximum total length of about 26 centimeters, placing it in the mid-range for butterflyfish species. Its compact, square-backed body shape is reflected in its common name 'squareback butterflyfish'.
Who described Western talma (Chelmonops curiosus) and when?
The species was formally named and described by the ichthyologist Rob F. I. Kuiter in 1986. It is classified in the order Acanthuriformes and the family Chaetodontidae, alongside other butterflyfish.
Why is Western talma (Chelmonops curiosus) notable to marine biologists?
Its strictly Australian range and preference for deeper reef habitats (51–57 m) set it apart from the many shallow-water butterflyfish that dominate coral-reef surveys. Because it occurs nowhere else, any population fluctuation is a concern for regional biodiversity monitoring.
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