Yellow-Striped Cardinalfish (Ostorhinchus cyanosoma) Care Guide
Ostorhinchus cyanosoma is a small Indo-Pacific cardinalfish with orange-yellow stripes that forms aggregations on sheltered reefs and is bred in captivity.
Compiled by Aquairi from published sources · Published · Updated
Overview
Ostorhinchus cyanosoma is a small marine cardinalfish of the family Apogonidae, described by Bleeker in 1853 and formerly placed in the genus Apogon. FishBase reports a bluish-silver body marked with about six orange-yellow stripes, with a maximum length around 8 cm.
Taxonomy
- Family: Apogonidae
- Genus: Ostorhinchus
- Scientific name: Ostorhinchus cyanosoma
- Common synonym: Apogon cyanosoma
Habitat
According to FishBase, the species ranges widely across the Indo-Pacific, from the Persian Gulf and Red Sea south to Mozambique, east to Fiji, and north to the Ryukyu and Bonin Islands. It lives in sheltered, clear-water reef areas in lagoons and on seaward reefs, typically at 1 to 15 m (recorded to 50 m), forming aggregations under ledges, in holes, or among sea-urchin spines.
Tank requirements
- Minimum tank volume: 150 L
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- GH: 8-12 °dGH
- Group size: at least 3 individuals
- Lifespan: 3-8 years
Diet
FishBase reports that the species feeds on planktonic crustaceans and small invertebrates, with a trophic level of about 3.6. In the aquarium it accepts small meaty marine foods.
Compatibility
It is a peaceful, aggregating species of the middle water column. It is well suited to calm marine communities with clownfish, tangs, wrasses and gobies, and should not be housed with large predators.
Breeding
FishBase records the species as a mouthbrooder with distinct pairing during courtship and spawning, and notes that it has been successfully reared in captivity.
Conservation status
IUCN Red List: Least Concern (assessed 2021), as reported by FishBase.
Ostorhinchus cyanosoma Breeding Guide
Overview
Ostorhinchus cyanosoma is a small cardinalfish ranging across the Indo-Pacific, from the Red Sea south to East Africa and east via western Australia and Queensland to New Caledonia (Wikipedia). Large examples grow to about 8 cm, with an average length near 6 cm. It is nocturnal and lives in clear lagoons and shallow reefs, sheltering under ledges, in holes and among the spines of sea urchins, where it often forms large aggregations containing stable male-female pairs.
Sexing
Males develop a wider gape and a more protruding lower jaw, an adaptation that lets them hold and circulate water over the egg mass during incubation (Wikipedia). Outside of brooding these differences are subtle, so the practical route is to grow a group and let stable pairs form on their own, since paired individuals show greater site fidelity than unpaired fish.
Conditioning
Conditioning relies on stable reef parameters and frequent feeding of small meaty foods. In the wild the species feeds on plankton and prefers small benthic sergestid crustaceans over planktonic larvae (Wikipedia), so enriched mysis, small marine crustaceans and finely chopped seafood offered about twice daily suit a breeding group well.
Breeding Setup
A breeding system reproduces the sheltered reef biotope: subdued lighting, ample rockwork with ledges and holes, and calm to moderate flow let a pair settle and feel secure. Because the species is nocturnal, low evening light and minimal disturbance encourage natural courtship, and a dedicated aquarium makes it easier to track which male is carrying eggs.
Spawning Behavior & Trigger
Spawning follows the apogonid pattern: the pair courts and the female transfers an egg mass that the male immediately takes into his mouth. As a paternal mouthbrooder (Wikipedia), the male fertilises and then orally incubates the clutch, and males do not feed during this period. Stable parameters and good condition rather than dramatic shifts drive repeated spawns in a settled pair.
Egg & Fry Care
The male carries the egg ball in his mouth, fasting until release, with the wider gape and protruding jaw aiding water circulation over the eggs (Wikipedia). Released larvae are small and pelagic; a separate rearing tank with very small first foods is needed, and the male can be left to brood undisturbed or moved to a quiet tank to reduce stress before release.
Common Challenges
The decisive obstacle is the larval phase rather than getting fish to pair or spawn. Small pelagic larvae require suitable micro-foods from first feeding, and a fasting brooding male is vulnerable to harassment, so keeping the breeding group calm and well fed between spawns is important.