Yellowstriped Cardinalfish

Geographic Origin and Biotope: Widespread in the tropical Indo-Pacific, from the Red Sea and East Africa to the Society Islands, north to southern Japan (Ryukyu Islands), and south to the Great Barrier Reef. Found in sheltered lagoons, seaward reefs, and amongst branching Acropora corals at depths of 1 to 50 meters.

Taxonomy and Morphology: Member of the family Apogonidae, also classified as Ostorhinchus cyanosoma. Features a short, compressed body and large eyes adapted for crepuscular life. Reaches a maximum size of about 8 cm.

Social Behavior: Peaceful and gregarious. During the day, it forms small schools that hover motionlessly between hard coral branches or cave entrances, dispersing at dusk to forage in open water.

Coloration and Sexual Dimorphism: Silvery blue-grey or bluish body with well-defined brilliant yellow-orange longitudinal stripes. Eyes feature distinct yellow stripes. No obvious external sexual dimorphism is visible.

Aquarium Setup: Requires a tank of at least 110 liters, though 150-200 liters is highly recommended to house a small group of 5-6 specimens. Provide live rock structures creating shaded overhangs, caves, and branching corals. Subdued lighting is preferred.

Diet and Feeding: Carnivorous and zooplanktivorous. Feed with small frozen foods like copepods, brine shrimp, and chopped mysis. Accepts dry pellets or flakes once acclimated. Feed twice daily.

Water Quality: Reef parameters are required: temperature 22-28°C, pH 8.0-8.5, specific gravity (SG) 1.020-1.025, GH 15-25, KH 8-12. Highly sensitive to organic buildup; regular maintenance is essential.

Compatibility and Tankmates: 100% reef safe. Perfect for reef aquariums with soft and hard corals. Coexists peacefully with other docile reef fish. Avoid large or aggressive tankmates. May eat tiny invertebrates.

Aquarium Reproduction: Paternal mouthbrooder. The male holds the fertilized eggs in his mouth for 7-10 days until hatching, during which he does not feed. Fry rearing is difficult.

Risks and Diseases: Hardy and long-lived. The main risk is starvation when housed with fast-feeding competitors. Sensitive to rapid water parameter fluctuations.