Hartzfeld's Cardinalfish (Apogon hartzfeldii) Care Guide
Apogon hartzfeldii is a benthic, nocturnal cardinalfish of the western Indo-Pacific that shelters on sheltered reef flats and shallow lagoons.
Compiled by Aquairi from published sources · Published · Updated
Overview
Apogon hartzfeldii is a marine cardinalfish of the family Apogonidae, described by Bleeker in 1852. FishBase treats it under the current valid name Ostorhinchus hartzfeldii and reports a maximum length around 12 cm; it is a benthic, nocturnal, reef-associated species.
Taxonomy
- Family: Apogonidae
- Genus: Apogon
- Scientific name: Apogon hartzfeldii
- Current valid name (FishBase): Ostorhinchus hartzfeldii (Bleeker, 1852)
Habitat
According to FishBase, the species occurs in Indonesia, the Philippines and Palau to Borneo, north-western Australia and the Arafura Sea, at depths of 1 to 28 m (usually 1 to 12 m). It inhabits sheltered reef flats and shallow lagoons, often among debris or corals.
Tank requirements
- Minimum tank volume: 200 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 assigns the species a carnivorous trophic level of about 3.6. As a nocturnal cardinalfish it feeds at night; in the aquarium it accepts meaty marine foods.
Compatibility
It is a peaceful species that occupies the middle water column and shelters by day. It suits calm marine communities with clownfish, tangs, wrasses and gobies, and should not be combined with large predators.
Breeding
FishBase records the species as a mouthbrooder with distinct pairing during courtship and spawning; the male incubates the eggs in his mouth.
Conservation status
IUCN Red List: Least Concern (assessed 2021), as reported by FishBase.
Apogon hartzfeldii Breeding Guide
Overview
Apogon hartzfeldii (now also placed in Ostorhinchus) is an Indo-Pacific cardinalfish ranging from Indonesia and the Philippines to Borneo, northwestern Australia and the Arafura Sea, reaching about 12 cm total length at depths of roughly 1 to 28 m (FishBase). It is a benthic, nocturnal species found in small groups among debris or corals of sheltered reef flats and shallow lagoons, also among massing long-spined urchins.
Sexing
External sexing is not documented for this species; the male is recognised by the larger head and jaw used to incubate eggs, as in other cardinalfish. Because the fish occurs in small groups, keeping several together and watching for distinct pairing is the practical route to a breeding pair.
Conditioning
Conditioning relies on stable reef parameters and frequent small meaty feeds. With a mid-level carnivorous trophic position (FishBase), the species takes enriched mysis, small marine crustaceans and finely chopped seafood; an evening feed matches its nocturnal habits and builds condition in a group.
Breeding Setup
A breeding setup recreates the sheltered reef-flat biotope: rubble, debris or branching coral for cover, plus subdued lighting and calm to moderate flow. A dedicated tank with minimal disturbance lets a pair settle and court at night, and makes a brooding male easy to follow.
Spawning Behavior & Trigger
The species are mouthbrooders showing distinct pairing during courtship and spawning (FishBase). The female transfers an egg mass to the male, who fertilises and orally incubates it; species-specific clutch counts and precise triggers are not given in the cited source and are therefore omitted, with stable conditions favouring repeated spawns.
Egg & Fry Care
The male carries the egg mass in his mouth and does not feed during incubation, the paternal oral-brooding pattern of the family. Released larvae are small and pelagic and require a separate rearing tank with very small first foods; the cited source confirms mouthbrooding but gives no species-level rearing protocol.
Common Challenges
As with related cardinalfish, the larval stage is the limiting factor rather than getting fish to pair. Small pelagic larvae need suitable micro-foods from first feeding, and the fasting brooding male must be protected from harassment, so a calm, well-fed group between spawns is important.