Spiny chromis (Acanthochromis polyacanthus)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Ovalentaria incertae sedis · Family: Pomacentridae · Genus: Acanthochromis.

Accepted name: Acanthochromis polyacanthus · Authority: (Bleeker, 1855) · Taxonomic status: accepted · AphiaID: 279469.

Synonyms and superseded combinations recorded for this taxon: Abudefduf jordani Seale, 1906; Acanthochromis polyacathus (Bleeker, 1855); Acanthochromis polycanthus (Bleeker, 1855); Acanthocromis polyacanthus (Bleeker, 1855); Chromis desmostigma Fowler & Bean, 1928; Dascyllus polyacanthus Bleeker, 1855; Heptadecanthus brevipinnis De Vis, 1885; Heptadecanthus longicaudis Alleyne & MacLeay, 1877; Heptadecanthus maculosus De Vis, 1885.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=279469 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 16 cm · Depth range: 1–65 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 13.3 of 100.

FishBase notes: Adults inhabit inshore and offshore coral reefs (Ref. 9710). Also found in harbors, lagoons and outer reef slopes. The only pomacentrid species that lacks a pelagic larval stage.

One of the very few marine fishes where fry are guarded by the parents (Ref. 9710, 48636). School as they grow and sub-adults are usually seen in small groups. Adults form pairs and are territorial when breeding (Ref. 48636).

Monogamous (Ref. 52884). Oviparous (Ref. 205). Eggs are demersal and adhere to the substrate (Ref. 205). Males guard and aerate the eggs (Ref. 205).

Source: FishBase species summary (SpecCode 6655) — https://www.fishbase.se/summary/Acanthochromis-polyacanthus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

7,724 georeferenced occurrence records for Acanthochromis polyacanthus are published through GBIF from 10 countries or marine areas. The map above plots 128 distinct locations from a sample of 3,000 records, omitting 9 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 (6,742); Solomon Islands (495); Indonesia (186); Philippines (157); Vanuatu (79).

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

Source: GBIF Occurrence Search (taxonKey 5212126) — https://www.gbif.org/occurrence/search?taxon_key=5212126&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=279469 (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 Acanthochromis polyacanthus (Bleeker, 1855) 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 188464) — https://www.iucnredlist.org/species/188464/0; GBIF IUCN Red List category endpoint (taxonKey 5212126) — https://api.gbif.org/v1/species/5212126/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

The spiny chromis was first formally described in 1855 as Dascyllus polyacanthus by the Dutch ichthyologist Pieter Bleeker with the type locality given as Batman in the Moluccas. It is the only species in the genus Acanthochromis. The genus name is a compound of acanthus meaning "spine", probably a reference to the 17 dorsal-fin spines, and Chromis, presumably referring to a relationship to that genus. The specific name polyacanthus means "many-spined".

Distribution and habitat

The spiny chromis is found in the western Pacific Ocean. It is found in western and central Indonesia, Papua New Guinea, northern Australia, and all the islands in the Philippines except Luzon.

They are also found in Melanesia. This fish usually lives in coral reefs. This fish is found at a depth range of 1 to 65 m but is usually found at a depth range of 4 to 20 m.

Description

Spiny chromis individuals can grow up to a maximum size of 14 cm as adults. Its fins have 17 dorsal spines, 14 to 16 dorsal rays, 2 anal spines, and 14 to 16 anal rays.

This species occurs in a wide range of colour variations, depending on geographic location. It is thought this is due to the lack of a pelagic larval phase and sedentary behaviour of adults, resulting in little genetic connectivity between populations and thus divergent evolution. It is currently unclear whether or not all these variations are truly the same species, or whether they constitute a species complex. Juveniles typically display a yellow stripe along their flanks.

Diet

This fish is planktivorous and algivorous, and steals algae from algae-farming species of damselfish.

similar to the behaviour of young discus.

Lifecycle

The spiny chromis, unlike many other coral reef fishes, has direct development of their larvae, which means that the parents protect their brood from the egg stage (which are laid on the reef), through hatching and onto the fully developed juvenile stage. There is no pelagic larval stage unlike the vast majority of coral reef fishes. This form of direct development means that the offspring often take up residence on the reef not far from where they were hatched. Consequently, high levels of local adaptation to their local environment has been recorded in this species, and a number of geographic colour variations have arisen.

Source: Wikipedia: Spiny chromis — https://en.wikipedia.org/wiki/Spiny_chromis (CC BY-SA 4.0). Accessed 2026-09-25.