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Half-banded Angel (Genicanthus semifasciatus) Care Guide

Genicanthus semifasciatus, the Japanese swallow, is a deep-water reef-safe angel from the Western Pacific, a protogynous hermaphrodite that feeds in midwater.

Overview

Genicanthus semifasciatus, the Japanese swallow, is a swallowtail angelfish of the family Pomacanthidae. FishBase records a maximum length of about 21.0 cm and describes it as a protogynous hermaphrodite, with sex change occurring at around 9.3 cm total length.

Taxonomy

  • Family: Pomacanthidae
  • Genus: Genicanthus
  • Scientific name: Genicanthus semifasciatus

Habitat

FishBase reports a Western Pacific range from southern Japan to Taiwan and the northern Philippines. It is marine, reef-associated and non-migratory, inhabiting seaward rocky and coral reefs at depths of about 15-100 m, placing it among the deep-water Genicanthus species.

Tank requirements

  • Minimum tank volume: 700 L (185 gal)
  • Temperature: 24-26 °C (75-79 °F)
  • pH: 8.1-8.4
  • dKH (carbonate hardness): 8-12
  • Lifespan: 10-15 years

Diet

FishBase describes the species as a herbivore-omnivore and a hardy aquarium fish that takes standard foods such as chopped meaty items, freeze-dried shrimp and mysids. Frequent small feedings of varied marine foods are appropriate.

Compatibility

It is a peaceful, mid-water angel. FishBase notes that it forms permanent harem groups of a single male with several smaller females. Suitable companions include tangs, wrasses, anthias and clownfish, while aggressive large Pomacanthus angels are best avoided.

Reef compatibility

As a midwater-feeding swallowtail, Genicanthus semifasciatus is regarded as reef-safe and generally ignores corals. Coming from deep water, it benefits from subdued lighting, with specific gravity around 1.024-1.026 and carbonate hardness of 8-12 dKH.

Conservation status

IUCN Red List: Least Concern (assessed 2009), as reported by FishBase.

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