Yellowstriped Cardinalfish (Ostorhinchus cyanosoma)

Description

Yellowstriped Cardinalfish (Ostorhinchus cyanosoma)

Local Pickup only

Overview

The Yellowstriped Cardinalfish (Ostorhinchus cyanosoma) is a striking and peaceful schooling species, easily recognized by its bright yellow horizontal stripes running along a silver body. Native to the Indo-Pacific, these fish are nocturnal by nature and often hover quietly in groups among branching corals or rocky crevices during the day. Their hardiness, small size, and calm temperament make them an excellent choice for both beginner and experienced reef keepers.

Appearance

• Coloration: Silver body with 5–6 vivid yellow stripes from head to tail

• Size: Reaches about 2–2.5 in (5–6 cm)

• Eyes: Large, adapted for low-light/night activity

• Behavior: Calm, prefers the safety of groups

Temperament & Compatibility

• Temperament: Peaceful and non-aggressive

• Best Kept: In small groups of 3+ to mimic natural schooling behavior

• Tankmates: Ideal with other peaceful reef-safe fish, including gobies, chromis, dartfish, and clownfish

• Caution: May be bullied by larger or aggressive species like triggers or dottybacks

Tank Requirements

• Tank Size: 30+ gallons (larger for bigger groups)

• Aquascape: Plenty of caves, rockwork, and coral branches for daytime shelter

• Placement: Mid-water column; often hover near rocks and corals

• Lighting: Moderate (they are more active in subdued or nighttime lighting)

• Flow: Moderate water movement preferred

Diet & Feeding

• Diet: Carnivorous – enjoy small meaty foods such as mysis shrimp, enriched brine shrimp, copepods, and finely chopped seafood

• Feeding Frequency: 2–3 times daily in small amounts

• Note: Will adapt to frozen and prepared foods but thrive with varied diets

Reef Compatibility

• Reef Safe: Yes – completely safe with corals, clams, and invertebrates

• Role: Adds color and movement to the reef without disturbing other inhabitants

Care Level

• Difficulty: Easy–Moderate

• Hardiness: Generally hardy once established

• Special Notes: Do best in groups; solitary individuals may become stressed

Breeding

• Type: Mouthbrooders – males incubate fertilized eggs in their mouths until hatching

• Aquarium Breeding: Possible but requires a dedicated setup to raise fry

Fun Facts 

• The Yellowstriped Cardinalfish is nocturnal, often hiding during the day and becoming more active under moonlight or dim conditions.

• Like many cardinalfish, they are mouthbrooders – the male protects the eggs in his mouth until the fry are ready to swim freely!

• They can form loose schools, creating a striking shimmering effect when kept in groups under reef lighting.