Longsnout butterflyfish (Prognathodes aculeatus)

Classification (WoRMS)

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

Accepted name: Prognathodes aculeatus · Authority: (Poey, 1860) · Taxonomic status: accepted · AphiaID: 273369.

Synonyms and superseded combinations recorded for this taxon: Chaetodon aculeatus (Poey, 1860); Chaetodon unicolor Sauvage, 1880; Chelmo pelta Günther, 1860; Chelmon aculeatus Poey, 1860.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273369 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

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

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

FishBase notes: Inhabit deep coral-rich reefs and drop-offs (Ref. 47838). Feed on small invertebrates. Often seen nibbling on the tube feet of sea urchins or the tentacles of tubeworms (Ref. 9710). Unlike some chaetodonts it does not pick parasites from the bodies of other fishes (Ref. 5521). Solitary, sometimes in pairs (Ref. 47838). Seek refuge when approached (Ref. 47838). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).

Source: FishBase species summary (SpecCode 3600) — https://www.fishbase.se/summary/Prognathodes-aculeatus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

20,947 georeferenced occurrence records for Prognathodes aculeatus are published through GBIF from 30 countries or marine areas. The map above plots 65 distinct locations from a sample of 3,000 records, omitting 4 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: United States of America (17,471); Puerto Rico (2,421); Virgin Islands (U.S.) (508); Guadeloupe (117); Colombia (91).

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

Source: GBIF Occurrence Search (taxonKey 2385596) — https://www.gbif.org/occurrence/search?taxon_key=2385596&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273369 (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 Prognathodes aculeatus (Poey, 1860) 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 165627) — https://www.iucnredlist.org/species/165627/0; GBIF IUCN Red List category endpoint (taxonKey 2385596) — https://api.gbif.org/v1/species/2385596/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The longsnout butterflyfish was first described in 1860 by Felipe Poey y Aloy and Albert C. L. G. Günther in two separate reports. Between them the fish was given three separate scientific names each one in a different genus, though Poey's assignment of the species to Prognathodes is the only valid combination. It was again described in 1880 by Sauvage who gave it yet another scientific name that has since been synonymized into P. aculeatus.

An average of 2 long, the longsnout butterflyfish is commonly known for its namesake long snout that is much more distinctive than those of similar species. They also have a dusky to yellow colored stripe that runs almost vertically from the top of the head to the eyes (unlike the stripes on other butterflyfishes which extend past the eyes).

The upper half of the longsnout butterflyfish is yellow that changes to orange and again darkens to brownish-orange. The dorsal fin of the fish is usually black.

Fairly common throughout its range, the longsnout butterflyfish is found on natural and artificial reefs, usually 30 in depth. It can be found off Florida, in the Gulf of Mexico, in the Caribbean Sea, and off the coast of Venezuela.

Longsnout butterflyfish are much more solitary than many other members of their family. They also inhabit deeper reefs and spend much of their time foraging in recesses for invertebrates. It is also known to eat the tube feet of sea urchins and tube worm tentacles. Unlike many other members of its family, the longsnout butterflyfish does not pick parasites from other fish.

Source: Wikipedia: Prognathodes aculeatus — https://en.wikipedia.org/wiki/Prognathodes_aculeatus (CC BY-SA 4.0). Accessed 2026-09-23.