Polleni grouper (Cephalopholis polleni) care guide

Group
Marine fish
Other names
Harlequin hind, Harlequin grouper, Harlequin cod, Harlequin rockcod, Blue-lined grouper
Family
Serranidae (groupers and sea basses)
Origin
Offshore islands in the Indian Ocean and western Pacific, from the Comoros to the Line Islands and French Polynesia; steep drop-offs, mostly 30–120 m.
Water
saltwater
Maximum size
43 cm
Temperature
24–27°C
pH
8.1–8.4
Hardness
Salinity SG 1.020–1.025
Minimum tank
900 litres
Care level
expert
Temperament
semi_aggressive
Reef safe
no

Care

Tank and decor: a large fish-only system with caves and overhangs and fairly subdued light, as it lives in caves on deep drop-offs. The tank size given is an estimate based on its adult size. Water: the sources give no species-specific figures, so the values here are general marine aquarium guidance: 24–27 °C, pH 8.1–8.4 and specific gravity 1.020–1.025. Keep nitrate low and the water well oxygenated. Behaviour: a solitary predator that often swims upside down along cave roofs. Identification: yellow-orange with blue horizontal lines. Trade and status: rare and only occasionally traded; usually collected from deep water. IUCN: Least Concern. Selling: our policies require the adult size and long-term tank needs to be stated clearly in the listing. Large fish must travel by a specialist live-animal courier (see the Livestock shipping guide). Sources: Wikipedia, List of marine aquarium fish species (en.wikipedia.org/wiki/Listofmarineaquariumfishspecies); Wikipedia (en.wikipedia.org/wiki/Cephalopholispolleni). Checked October 2026.

Diet

Eats smaller fish and crustaceans. Offer meaty marine foods such as fish, prawn, squid and mysis.

Breeding

Not described in the sources, and not bred in home aquaria.

Compatibility and tank mates

Not reef safe: eats small fish and crustaceans. Keep with large, robust fish.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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