Chronixis Surgeonfish

Geographic Origin and Biotope: Tropical Western Pacific. Rare species, endemic to the Kapingamarangi Atoll in the Caroline Islands, inhabiting outer coral reefs down to 30 meters.

Taxonomy and Morphology: Member of the family Acanthuridae. Reaches about 21 cm. Oval, laterally compressed body with small teeth suited for scraping algae from rocks.

Social Behavior: Active swimmer and semi-aggressive fish. Juveniles mimic the appearance of dwarf angelfish of the genus Centropyge to escape predators.

Coloration and Sexual Dimorphism: Uniform dark brownish-purple body coloration with a black shoulder patch and a slightly rounded caudal fin. No sexual dimorphism.

Aquarium Setup: Needs a spacious aquarium of at least 470 liters (125 gallons) with strong water movement and ample open areas for fast swimming.

Diet and Feeding: Herbivore. In the aquarium, it must be fed abundantly with nori seaweed, spirulina, veggie pellets, and plant-based frozen foods.

Water Quality: Temperature 22-26°C (72-78°F), pH 8.1-8.4, specific gravity 1.020-1.025. Demands powerful skimming to keep oxygen levels high.

Compatibility and Tankmates: 100% reef-safe. Does not damage corals but can compete aggressively for food with other similarly shaped surgeonfish.

Aquarium Reproduction: Reproduction in the hobby is not successfully documented due to the complex pelagic larval phase.

Risks and Diseases: Equipped with a sharp, retractable caudal spine on the sides of the tail base. Exercise caution during handling. Highly sensitive to skin diseases.