Capricorn cardinalfish (Ostorhinchus capricornis)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Apogoniformes · Family: Apogonidae · Genus: Ostorhinchus.

Accepted name: Ostorhinchus capricornis · Authority: (Allen & Randall, 1993) · Taxonomic status: accepted · AphiaID: 713302.

Synonyms and superseded combinations recorded for this taxon: Apogon capricornis Allen & Randall, 1993.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=713302 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

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

Maximum length: 5.760000228881836 cm · Depth range: 2–15 m · Habitat zone: reef-associated · Body shape: fusiform / normal · Vulnerability index: 10 of 100 · Aquarium trade: never/rarely.

FishBase notes: Benthic species which inhabits coral reef (Ref. 75154).

Source: FishBase species summary (SpecCode 46519) — https://www.fishbase.se/summary/Ostorhinchus-capricornis.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Distribution and occurrence records (GBIF)

194 georeferenced occurrence records for Ostorhinchus capricornis are published through GBIF from 5 countries or marine areas. The map above plots 42 distinct locations from a sample of 194 records, omitting 3 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 (183); New Caledonia (6); Norfolk Island (3); Indonesia (1); Solomon Islands (1).

Source: GBIF Occurrence Search (taxonKey 7193058) — https://www.gbif.org/occurrence/search?taxon_key=7193058&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=713302 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-25.

Description and natural history (Wikipedia)

Ostorhinchus capricornis is dusky yellow in colour, this lightens to bronze or golden yellow on the ventral surface. It has a black spot around the caudal peduncle and it has two "neon" blue stripes which run through the eye, the lower stripe extending to the posterior edge of the operculum. It grows to a maximum standard length of 5.8 cm. It is similar to the yellow cardinalfish (Ostorhinchus flavus) but that species has white stripe through the eye rather than the neon blue stripes of O. capricornis.

Ostorhinchus capricornis is named after the Capricorn Group of islands in southern Great Barrier Reef, Queensland, where most of the specimens have been collected. It also occurs on reefs in the southern Coral Sea, at least as far south as Sydney in New South Wales and with juveniles have been recorded as far south as Montague Island. They are also found around Lord Howe Island and Norfolk Island in the Tasman Sea and in the tropical, south-west Pacific around the Chesterfield Islands, Coral Sea, and New Caledonia.

Ostorhinchus capricornis is associated with reefs at depths of 2-15 m and they normally spend the day sheltering in caves and crevices. Small groups emerge from their daytime shelters at dusk and they feed on benthic invertebrates and zooplankton. They form pairs which demonstrate courtship behaviours before spawning and the male then broods the eggs in his mouth.

Source: Wikipedia: Ostorhinchus capricornis — https://en.wikipedia.org/wiki/Ostorhinchus_capricornis (CC BY-SA 4.0). Accessed 2026-09-25.