Eastern talma (Chelmonops truncatus)

Classification (WoRMS)

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

Accepted name: Chelmonops truncatus · Authority: (Kner, 1859) · Taxonomic status: accepted · AphiaID: 280142.

Synonyms and superseded combinations recorded for this taxon: Chaetodon truncatus Kner, 1859; Chelmo trochilus Günther, 1874; Chelmo truncatus (Kner, 1859); Chelmonops trochilus (Günther, 1874).

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=280142 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 22 cm · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 12 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Found on rocky reefs (Ref. 9563). Usually in pairs. Feed on algae and small invertebrates (Ref. 4859). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).

Source: FishBase species summary (SpecCode 10286) — https://www.fishbase.se/summary/Chelmonops-truncatus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

1,417 georeferenced occurrence records for Chelmonops truncatus are published through GBIF from 4 countries or marine areas. The map above plots 63 distinct locations from a sample of 1,417 records, omitting 19 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 (1,402); Cuba (1); Norfolk Island (1); Philippines (1).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2385297) — https://www.gbif.org/occurrence/search?taxon_key=2385297&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=280142 (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 Chelmonops truncatus (Kner, 1859) 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 165720) — https://www.iucnredlist.org/species/165720/0; GBIF IUCN Red List category endpoint (taxonKey 2385297) — https://api.gbif.org/v1/species/2385297/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

Chelmonops truncatus bears a close resemblance to the Western talma (C. curiosus), the main difference being that the dorsal fin is truncated, compared to the long filament present on the western species. The fins and dark bands on the body are often tinged vinaceous, giving them a dark, red appearance in some light. Like other butterflyfishes the juveniles have an obvious ocellus on the dorsal fin, but this smudges and becomes less obvious as the fish matures.

The smooth profile of the rear part of the dorsal fin is more obvious in younger fish, and this part of the fin becomes slightly elongated in adults. The rear margin of the soft dorsal and anal fins is almost vertical in adults, the fins are more rounded in juveniles. This species attains a maximum total length of 22 cm.

Chelmonops truncatus is endemic to south eastern Australia where it occurs from Double Island Point in southern Queensland south to around Jervis Bay in New South Wales.

Chelmonops truncatus is found in coastal bays and estuaries where they live along deep rocky walls. The adults are normally found in pairs, while the juveniles are frequently encountered alone. Their diet comprises small crustaceans, worms, and filamentous algae. Pairs defend territories.

Chelmonops truncatus is rare in the aquarium trade and is almost never exported from Australia.

Chelmonops truncatus was first formally described in 1859 as Chaetodon truncatus by the austrian ichthyologist Rudolf Kner (1810-1869) with the type locality given as Sydney. The Dutch ichthyologist Pieter Bleeker (1819-1878) created the genus Chelmonops in 1876 as a monotypic genus with this species as its only member. C. truncatus is, therefore, the type species of Chelmonops.

Source: Wikipedia: Chelmonops truncatus — https://en.wikipedia.org/wiki/Chelmonops_truncatus (CC BY-SA 4.0). Accessed 2026-09-25.