
Sargocentron diadema
Family: Holocentridae ยท Squirrelfish & Soldierfish
Also known as: Diadem Squirrelfish, Barred Squirrelfish, Crown-of-Thorns Squirrelfish
The Crown Squirrelfish is a handsome nocturnal reef dweller that features a vibrant red body accented by bold white horizontal stripes running along the flanks, creating a striking visual pattern that stands out even in dimly lit aquariums. Its large, dark eyes are perfectly adapted for low-light hunting, and a prominent spine on the gill cover serves as a defensive weapon. The name 'crown' refers to the spine arrangement on the head, which gives the impression of a small diadem or crown.
In the wild, the Crown Squirrelfish is widely distributed across Indo-Pacific coral reefs, from the Red Sea to Hawaii, at depths ranging from 1 to 30 meters. It is a strictly nocturnal species that shelters in caves, under ledges, and within coral formations during the day, often found in small aggregations sharing the same hiding spot. At night, it ventures out across the reef to hunt for small crabs, shrimp, polychaete worms, and other benthic invertebrates, relying on its exceptional night vision and sensitive lateral line system to locate prey.
At a maximum size of about 7 inches, the Crown Squirrelfish is one of the more moderately sized members of its family, making it suitable for aquariums of 75 gallons or larger. It is a hardy, long-lived species that acclimates well to captivity once it adjusts to the aquarium environment. Subdued lighting with ample caves and overhangs is important for its comfort, and moonlight or actinic lighting allows keepers to observe its natural nighttime activity. The Crown Squirrelfish is peaceful toward most tankmates but may consume very small ornamental shrimp.
Crown Squirrelfish are nocturnal carnivores that feed on small crabs, shrimp, worms, and zooplankton. In captivity, offer frozen mysis shrimp, enriched brine shrimp, chopped krill, and marine pellets. They may prefer to eat during dim lighting initially but will adapt to daytime feeding over time. Feed two to three times daily, with an evening feeding being especially beneficial.
The Crown Squirrelfish is peaceful toward most tankmates and makes an excellent community fish for a dimly lit display. Safe with corals and most invertebrates, though very small shrimp may be at risk. Compatible with tangs, angelfish, clownfish, wrasses, and other community species. Can be kept in small groups in larger tanks. Avoid very aggressive species that may outcompete it for cave hiding spots.
Check CompatibilityCrown Squirrelfish are pelagic spawners that release buoyant eggs into the water column at dusk. The larvae are planktonic and undergo an extended developmental phase. Captive breeding has not been achieved in home aquariums.