Genicanthus semifasciatus, commonly known as the Japanese Swallowtail Angelfish, is a visually striking species prized for its elegant colouration and peaceful temperament. Sold as a pair, these angelfish are suitable for experienced hobbyists with adequately sized marine aquariums.
Care Level: Moderate to advanced. This species requires stable water parameters and a mature tank environment.
Temperament and Compatibility: Genicanthus semifasciatus is generally peaceful and can be kept with other non-aggressive tankmates. They are less territorial than many other angelfish species but should be introduced carefully to avoid stress. Suitable tankmates include other peaceful fish and invertebrates.
Diet: Omnivorous. Provide a varied diet including high-quality marine angelfish pellets, frozen mysis shrimp, brine shrimp, and marine algae. Supplement with vegetable matter to mimic natural feeding habits.
Minimum Tank Size: A minimum of 180 litres (approximately 50 gallons) is recommended to provide ample swimming space and reduce territorial behaviour.
Lighting and Water Flow: Standard reef aquarium lighting is sufficient. Moderate water flow replicates natural conditions and helps maintain fish health.
Placement: Mid to upper levels of the aquarium are preferred. Provide plenty of live rock for grazing and shelter.
Origin: Native to the Western Pacific, particularly around Japan.
Maximum Size: Up to 15 cm (6 inches) in length.
When purchasing a pair, it is important to introduce them simultaneously to reduce aggression and encourage pairing behaviour. Regular water changes and stable water chemistry will ensure optimal health.
