Lagoon damselfish (Hemiglyphidodon plagiometopon)

Classification (WoRMS)

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

Accepted name: Hemiglyphidodon plagiometopon · Authority: (Bleeker, 1852) · Taxonomic status: accepted · AphiaID: 212961.

Synonyms and superseded combinations recorded for this taxon: Abudefduf melanopselion Fowler, 1918; Glyphidodon plagiometopon Peters, 1876; Glyphisodon batjanensis Bleeker, 1855; Glyphisodon plagiometopon Bleeker, 1852; Hemiglyphidodon plagiometapon (Bleeker, 1852); Hemiglyphidon plagiometopon (Bleeker, 1852).

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=212961 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 18 cm · Depth range: 1–20 m · Habitat zone: reef-associated · Body shape: short and / or deep · Vulnerability index: 10 of 100 · Fishery importance: minor commercial · Aquarium trade: commercial.

FishBase notes: Adults occur in protected lagoon and coastal reefs around branching corals (Ref. 9710), usually with lots of algae on coral bases on the substrate (Ref. 48636). Feed on algae (Ref. 1602). Large species, to at least 18 cm (Ref. 48636). Oviparous, distinct pairing during breeding (Ref. 205).

Eggs are demersal and adhere to the substrate (Ref. 205). Males guard and aerate the eggs (Ref. 205). Diurnal species (Ref. 113699).

Source: FishBase species summary (SpecCode 5487) — https://www.fishbase.se/summary/Hemiglyphidodon-plagiometopon.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

1,008 georeferenced occurrence records for Hemiglyphidodon plagiometopon are published through GBIF from 15 countries or marine areas. The map above plots 130 distinct locations from a sample of 1,008 records, omitting 24 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 (432); New Caledonia (176); Indonesia (93); Philippines (84); Palau (79).

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

Source: GBIF Occurrence Search (taxonKey 2398183) — https://www.gbif.org/occurrence/search?taxon_key=2398183&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=212961 (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 Hemiglyphidodon plagiometopon (Bleeker, 1852) 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 188468) — https://www.iucnredlist.org/species/188468/0; GBIF IUCN Red List category endpoint (taxonKey 2398183) — https://api.gbif.org/v1/species/2398183/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

The lagoon damselfish is a large brown species of damselfish, often the adults have a pale russet head and the colour of the fish gradually darkens towards the tail. There are pinkish markings on the operculum.

The juveniles are dark blue to brownish on the head and near body and are yellow towards the tail and on the underside with a large iridescent blue eyespot on the dorsal fin, and blue bands and spots near the head on its body. They grow to a maximum length of 18 cm. Sometimes the only distinctive marking is a yellow eyering.

Distribution

The lagoon damselfish is found in the eastern Indian Ocean from Thailand through Indonesia, the Philippines and the Timor Sea into the western Pacific where it is found south to Australia and north to China and east to the Solomon Islands.

Habitat and biology

The lagoon damselfish is found in sheltered reefs and lagoons, often in areas of high turbidity and a silty substrate at the base of branching corals. They are found at depths of 1-20 m. They are detritovores and the species has up to three times the number of gill rakers than other damselfish which are for feeding on fine detritus. They are territorial and defend a patch of algal covered reef.

While feeding on detritus they will consume small amounts of algae and invertebrates. They form pairs for breeding, clearing an area to create a nest, then they begin in a mating dance which involves fast swimming and movements of the fins. While mating, the males frequently darken and may develop white blotches. The eggs are laid at dawn, and are demersal which adhere to the substrate where the male guards and aerates them.

Conservation

The lagoon damselfish has been evaluated for the IUCN Red List of Threatened Species as Least Concern, but it may be threatened by habitat degradation and by human exploitation.

Source: Wikipedia: Lagoon damselfish — https://en.wikipedia.org/wiki/Lagoon_damselfish (CC BY-SA 4.0). Accessed 2026-09-25.