Harlequin sweetlips (Plectorhinchus chaetodonoides)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Eupercaria incertae sedis · Family: Haemulidae · Genus: Plectorhinchus.

Accepted name: Plectorhinchus chaetodonoides · Authority: Lacepède, 1801 · Taxonomic status: accepted · AphiaID: 273483.

Synonyms and superseded combinations recorded for this taxon: Gaterin chaetodonoides (Lacepède, 1801); Plectorhinchus chaetodontoides Lacepède, 1801; Plectorhinchus chaetodontonoides Lacepède, 1801; Plectorhincus chaetodonoides Lacepède, 1801; Plectorhynchus chaetodonoides (Lacepède, 1801); Plectorhynchus chaetodontoides (Lacepède, 1801); Plectorhynchus chaetonoides Lacepède, 1801; Plectorynchus chaetodonoides (Lacepède, 1801).

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273483 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 72 cm · Common length: 60 cm · Depth range: 1–30 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 48.8 of 100 · Fishery importance: minor commercial · Aquarium trade: commercial.

FishBase notes: Inhabits coral-rich areas of clear lagoon and seaward reefs. Adults are solitary, near and under ledges or caves by day. Juveniles are found among corals (Ref. 9710). Feeds on crustaceans, mollusks, and fishes at night.

Juveniles are used in the aquarium industry (Ref. 9137). Small juveniles may mimic a toxic flatworm (Ref. 9710). Marketed fresh, a small quantity is salted. Large fish have coarse and dry flesh (Ref. 47695).

Source: FishBase species summary (SpecCode 6364) — https://www.fishbase.se/summary/Plectorhinchus-chaetodonoides.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

2,794 georeferenced occurrence records for Plectorhinchus chaetodonoides are published through GBIF from 33 countries or marine areas. The map above plots 329 distinct locations from a sample of 2,794 records, omitting 59 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 (864); Indonesia (528); Philippines (373); New Caledonia (276); Malaysia (114).

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

Source: GBIF Occurrence Search (taxonKey 2382701) — https://www.gbif.org/occurrence/search?taxon_key=2382701&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273483 (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 Plectorhinchus chaetodonoides Lacepède, 1801 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 68372590) — https://www.iucnredlist.org/species/68372590/0; GBIF IUCN Red List category endpoint (taxonKey 2382701) — https://api.gbif.org/v1/species/2382701/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

Plectorhinchus chaetodonoides has fleshy lips which become moderately swollen as the fish grows, there are 6 pores on the chin but no central pit.< The dorsal fin typically has 12 spines, although rarely it has 11 spines. and 18–20 soft rays, the soft rayed part of the dorsal fin has a height which is roughly equal to the length of its base. The juveniles are brownish with large, discrete creamy white blotches on the body these develop brown spotting as the fish matures.

As they grow into adults the coloration slowly develops a greyish background colour broken large, dark brown spots, these spots having a greater diameter of the iris. The maximum recorded total length is 72 cm, although 60 cm is more typical, and the maximum published weight is 7 kg. It is thought that the juveniles are Batesian mimics of poisonous flatworms. The caudal fin of juveniles is deeply forked and has wide rounded lobes both of which are mostly white marked with a large brown spot, in adults it is much less forked.

Distribution

Plectorhinchus chaetodonoides is distributed across the eastern Indian Ocean and the western Pacific Ocean from the Maldives and Mauritius east as far as Tonga, north to the Ryukyu Islands and south to the Great Barrier Reef. One was seen off St. Martin in the West Indies in 2007, considered to be probably a deliberately released individual from an aquarium.

Habitat and biology

Plectorhinchus chaetodonoides is found in coral-rich parts of clear lagoons and on seaward reefs. The adults are solitary fish, living in the vicinity of and sheltering beneath ledges or caves during the day.

The juveniles are found sheltering in corals. It is a carnivorous species which preys on benthic invertebrates such as crustaceans and molluscs, as well as fishes, which it forages for during the night. The juveniles typically swim in a head down posture wildly undulating their fins as they swim, a behaviour which may mimic toxic or distasteful platyhelminths or nudibranchs and so provide some protection from predation.

Systematics

Plectorhinchus chaetodonoides was first formally described in 1801 by the French naturalist Bernard Germain de Lacépède with no type locality given but it is likely to have been somewhere in modern Indonesia. The specific name chaetodonoides means having the form of Chaetodon which when Lacépède described this species referred to both butterflyfishes and marine angelfishes and is an allusion to the serrated operculum, similar to that of marine angelfish, and the then presumption of a close taxonomic relationship between this species and the genus Chaetodon.

Utilisation

Plectorhinchus chaetodonoides are caught using handlines and spear. The fish caught are marketed fresh, although some are preserved by salting. The meat of larger specimens has been described a "coarse and dry". The small, colourful juveniles are collected for the aquarium trade and there may be overexploitation in some areas.

Source: Wikipedia: Plectorhinchus chaetodonoides — https://en.wikipedia.org/wiki/Plectorhinchus_chaetodonoides (CC BY-SA 4.0). Accessed 2026-09-25.