Orbiculate Cardinalfish (Sphaeramia orbicularis) Care Guide
Sphaeramia orbicularis is an Indo-Pacific cardinalfish of sheltered coastal shores and mangroves, reaching about 10 cm.
Compiled by Aquairi from published sources · Published · Updated
Overview
Sphaeramia orbicularis, the orbiculate cardinalfish, was described by Cuvier in 1828. It is a cardinalfish of the family Apogonidae reaching a maximum total length of about 10 cm, distinguished by a dark vertical band across the body and scattered dark spots toward the tail.
Taxonomy
- Family: Apogonidae
- Genus: Sphaeramia
- Scientific name: Sphaeramia orbicularis (Cuvier, 1828)
- Common names: Orbiculate cardinalfish, polka-dot cardinalfish
Habitat
According to FishBase, the species ranges across the Indo-Pacific from East Africa to Kiribati, north to the Ryukyu Islands and south to New Caledonia. It is restricted to shallow sheltered coastal waters among mangroves, rocks, debris and piers at depths of 0-5 m.
Tank requirements
- Minimum tank volume: 150 L (40 gal)
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Carbonate hardness: 8-12 °dGH
- Maximum size: about 10 cm total length (FishBase)
- School size: keep in small groups (3 or more)
- Lifespan: 3-8 years
Diet
FishBase describes the species as a nocturnal feeder on planktonic crustaceans, with a trophic level of about 3.6. In aquaria it accepts meaty frozen and prepared foods, ideally offered when the tank lights are dimmed.
Compatibility
This is a peaceful, mid-water cardinalfish that is most settled in small groups. It should be kept with similarly calm tankmates and away from large predatory fishes.
Breeding
FishBase reports paternal mouthbrooding: males incubate up to about 12,000 eggs for roughly eight days, with spawning on semi-lunar cycles. Females reach sexual maturity at about 6 cm and males at about 7 cm.
Conservation status
IUCN Red List: Least Concern (assessed 2021).
Sphaeramia orbicularis Breeding Guide
Overview
Sphaeramia orbicularis, the orbiculate cardinalfish, is a member of the family Apogonidae reaching about 10 cm total length, with a common length near 8.9 cm. It occurs throughout much of the Indo-Pacific from East Africa to Kiribati, north to the Ryukyu Islands and south to New Caledonia, at depths of 0 to 5 m, often in mangrove and estuarine shallows. It feeds mainly on planktonic crustaceans at night. The species is a paternal mouthbrooder, making it one of the more accessible marine fishes for captive reproduction.
Sexing
Mature males of cardinalfishes have a larger jaw and longer head that accommodates the egg mass during incubation, which is the most reliable distinguishing feature. According to FishBase, males of this species reach sexual maturity at about 7 cm and females at about 6 cm. Outside the breeding period the sexes are otherwise similar in coloration.
Conditioning
Adults condition well on a varied carnivorous diet reflecting their natural intake of planktonic crustaceans, fed in the evening to match their nocturnal feeding habit. Keeping a small group lets a compatible pair form naturally. The species tolerates the lower-salinity conditions of its mangrove and estuarine habitat, but stable, mature water best supports spawning.
Spawning Behavior & Trigger
Courtship and spawning occur on a semi-lunar cycle, shortly before the full and new moons. After pairing, the female releases eggs that the male takes into his mouth and fertilises, forming a cohesive egg mass. FishBase reports that males incubate up to about 12,000 eggs.
Egg & Fry Care
The male broods the egg mass in his mouth for about 8 days, during which he does not feed; many cardinalfishes show breeding-specific male jaw coloration that helps conceal the eggs. The larval phase is pelagic, and after settlement juveniles grow at roughly 3 to 6 mm per month. Rearing the planktonic larvae requires small live first foods, so a dedicated larval system separate from the display is needed for grow-out.
Common Challenges
The main difficulties are protecting the brooding male from harassment so he does not prematurely release or swallow the eggs, and rearing the small pelagic larvae through their first-food stage. Because the larvae are planktonic rather than the larger, advanced young of some other cardinalfishes, larval feeding is the principal bottleneck.