Blue Eye Cardinalfish - Ostorhinchus compressus

Blue Eye Cardinalfish (Ostorhinchus compressus)

The Blue Eye Cardinalfish, Ostorhinchus compressus, is a peaceful and attractive marine cardinalfish, recognised for its slender body, subtle striped patterning and beautiful iridescent blue eyes. Also known as the Ochre-Striped Cardinalfish or Blue-Eyed Cardinalfish, this species brings a calm, natural reef look to mature marine aquariums. It is well suited to peaceful reef communities, especially when kept with gentle tank mates and provided with rockwork or branching coral-style shelter.

Common Name:
Blue Eye Cardinalfish, Blue-Eyed Cardinalfish, Ochre-Striped Cardinalfish, Split-Banded Cardinalfish.

Scientific Name (Latin):
Ostorhinchus compressus

Maximum Size:
Up to around 12 cm, though many aquarium specimens are usually smaller.

Water Type:
Marine

Origin / Natural Habitat:
Found across the Indo-West Pacific, including areas from the Andaman Sea through to the Western Pacific, southern Japan, Australia, New Caledonia and Vanuatu. In the wild, Blue Eye Cardinalfish are usually found in small groups around coral-rich reef areas, especially close to branching corals such as Acropora and Porites. They often shelter among coral branches during the day and become more active during lower-light periods.

Water Parameters:
Temperature: 24–27°C
pH Range: 8.1–8.4
Hardness or Salinity: SG 1.020–1.025

Temperament:
Peaceful. Blue Eye Cardinalfish are generally suitable for calm marine community aquariums and reef systems. They should be kept with peaceful to moderately active fish and should not be housed with aggressive predators, large hawkfish, boisterous wrasses or fish that may intimidate them. They can be kept singly, in pairs or in small groups where space allows.

Diet:
Carnivorous planktivore. In the aquarium, offer a varied diet of frozen mysis shrimp, enriched brineshrimp, cyclops, copepod-based foods, finely chopped meaty marine foods and quality small marine pellets. Smaller, regular feeds are ideal, especially while settling, as cardinalfish naturally feed on small suspended foods and tiny crustaceans.

Minimum Tank Size:
A practical minimum of around 100 litres is recommended for a single specimen or pair, with larger aquariums preferred for groups. Provide mature rockwork, caves, overhangs, branching coral-style shelter and calmer areas where the fish can rest during the day.

Behaviour & Activity:
A calm and often hovering cardinalfish that tends to stay close to shelter during the day. It may spend time around branching coral, rock overhangs or shaded areas before becoming more active during evening and lower-light periods. In suitable aquariums, Blue Eye Cardinalfish may form loose groups, creating a natural and peaceful display. Like many cardinalfish, they are mouthbrooders, with males carrying eggs during breeding. A secure lid is recommended, as startled marine fish can jump.

Reef Safe:
Reef Safe
Blue Eye Cardinalfish are considered reef safe and do not normally nip corals, clam mantles or sessile invertebrates. They are a good choice for peaceful reef aquariums, although very tiny crustaceans and natural microfauna may be eaten as part of their normal feeding behaviour.

Special Requirements or Care Notes:
Best kept in a mature, peaceful marine aquarium with plenty of shelter and stable water quality. Avoid aggressive or fast-feeding tank mates that may prevent them from feeding properly. If keeping a group, introduce them together where possible and provide enough space and visual cover. This species can be shy at first, so gentle acclimation, low-stress introduction and smaller regular feeds are recommended.

Suitable for:
Beginner to Intermediate fishkeepers

Availability:
Occasionally available in the marine aquarium trade / Availability can vary depending on supplier, import and group size

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.