Blue Stripe Grouper - Cephalopholis formosa

Blue Stripe Grouper (Cephalopholis formosa)

The Blue Stripe Grouper is a striking marine grouper with a warm brown to yellow-brown body covered in fine electric-blue lines across the head, body and fins. In the wild it is usually found alone on shallow silty or dead reef areas, where it uses cover to ambush smaller prey. In captivity it can make a bold, intelligent display fish, but it is still a predatory grouper that needs a spacious, mature marine aquarium and carefully chosen tankmates.

Common Name:
Blue Stripe Grouper. It is also commonly known as the Bluelined Hind or Blue-lined Rockcod.

Scientific Name (Latin):
Cephalopholis formosa

Maximum Size:
Up to 34 cm in length.

Water Type:
Marine.

Origin / Natural Habitat:
Found in the Indo-West Pacific, from the eastern Indian Ocean across to the western Pacific, including records from India and Sri Lanka to the Philippines, north to southern Japan and south to northern Australia. It is typically associated with shallow coastal reefs, especially silty or dead reef areas rather than highly exposed reef crests.

Water Parameters:
Temperature: 23–27°C
pH Range: 8.1–8.4
Salinity: 1.020–1.025 SG
These are sensible stable aquarium conditions for long-term captive care of this species.

Temperament:
Semi-aggressive to aggressive. This species is a predatory grouper and may eat smaller fish or ornamental crustaceans if given the chance, so it should be kept with suitably robust tankmates only.

Diet:
Carnivorous. In the wild it feeds mainly on small fishes and crustaceans. In captivity it should be offered a varied diet of meaty marine foods such as shrimp, squid, chopped fish and other protein-rich marine fare.

Minimum Tank Size:
A practical long-term recommendation is 950 litres or more, as this species becomes a sizeable predatory fish that benefits from substantial swimming room, hiding areas and strong filtration.

Behaviour & Activity:
This is a solitary, ambush-oriented grouper that spends much of the day close to rockwork or reef structure, watching for prey and making short bursts to feed. It is generally less frenetic than many wrasses or tangs, but it still needs secure shelter and open room to move.

Reef Safe:
Reef Safe with Caution
It is generally unlikely to damage corals directly, but caution is essential because it may eat ornamental shrimps, small crabs and smaller fish. In a reef aquarium, monitor carefully around mobile invertebrates and bite-sized tankmates.

Special Requirements or Care Notes:
Best kept in a well-established marine aquarium with strong filtration, stable water quality, secure rockwork and carefully planned stocking. This species is better suited to a predator-style or robust fish community setup than a delicate mixed reef with small ornamental livestock.

Suitable for:
Experienced fishkeepers. That recommendation is based on its predatory nature, adult size and need for a spacious aquarium with appropriate tankmate selection.

Availability:
Occasional in trade. It does appear in the marine aquarium trade, but it is more of a specialist predator species than a routine community fish.