Ochre-striped Cardinalfish

Geographic Origin and Biotope: Widespread in the tropical Indo-Pacific, from Indonesia and the Philippines to Samoa, north to southern Japan, and south to the Great Barrier Reef. Inhabits protected lagoons, shallow reefs, and branching Porites coral patches at depths of 2 to 20 meters.

Taxonomy and Morphology: Member of the family Apogonidae, scientifically classified as Ostorhinchus compressus. Features a laterally compressed body and large neon blue eyes adapted for nocturnal vision. Reaches approximately 10 cm in length.

Social Behavior: Peaceful and schooling species. During the day, they hover motionless in groups within caves or shaded coral branches, becoming active at night to hunt for zooplankton.

Coloration and Sexual Dimorphism: Whitish body crossed by 6 longitudinal ochre or reddish-brown stripes. Eyes are bright neon blue with dark markings. No obvious external sexual dimorphism, though males display slightly wider jaw structures when mouthbrooding.

Aquarium Setup: Demands at least 115 liters for a single specimen, but a 200-liter tank is preferred to maintain a group of 5 or more. Provide live rock structures creating caves, shaded overhangs, and branching corals. Subdued lighting is appreciated.

Diet and Feeding: Carnivorous. Feeds mainly on zooplankton. In captivity, feed with small frozen foods like mysis, brine shrimp, and chopped krill. Accepts quality pellets after acclimation. Feeding at dusk or dawn is recommended.

Water Quality: Stable parameters: temperature 22-28°C, pH 8.0-8.5, specific gravity (SG) 1.020-1.025, GH 15-25, KH 8-12. Sensitive to high nitrates and phosphates; requires good skimming and regular water changes.

Compatibility and Tankmates: 100% reef safe. Perfect for coral reef tanks. Coexists peacefully with other docile fishes of similar size. Avoid aggressive tankmates that might intimidate them. May prey on tiny ornamental shrimps.

Aquarium Reproduction: Paternal mouthbrooder. After fertilization, the male holds the egg mass in his mouth, guarding and aerating them for about a week without feeding. Fry hatch at night. Rearing the fry is complex.

Risks and Diseases: Hardy and easy to care for. May suffer from starvation if housed with aggressive, fast-feeding competitors. Susceptible to marine ich (Cryptocaryon) under temperature stress.