Japanese Swallowtail Angelfish

From Microcosm Aquarium Explorer

Jump to: navigation , search
Genicanthus melanospilos - (Bleeker, 1857)
Japanese Swallowtail Angelfish

Male with vertical bars and long tail streamers. Scott W. Michael


Among the best of their family for a reef aquarium, the Genicanthus swallowtail angelfishes are elegant fishes that put on a constant daytime show, actively hunting with other planktivores in the water column. This species is one of the most durable members of the genus.

Adults of this species are often found in male-female pairs or in harems with a small aggregation of females and one dominant male.

Because they are so active, they do best in an aquarium with plenty of swimming room and strong currents. A low reef profile or a reef wall that leaves the front two-thirds of the tank open suits them well.

All Genicanthus angels must be fed multiple times each day.

Female lacks vertical bars.

This species and the Lamarck's Angelfish are considered much more hardy and easily kept than others in the genus.

They tend to command premium prices because they are most abundant in the wild at depths of 20 to 50 m (66 to 164 ft.).

Family: Pomacanthidae

Other common name(s):

  • Blackspot Angelfish
  • Zebra Angelfish

Native range:

Habitat: Open water above or near a rocky reef structure of live rock that offers caves and other hiding spaces.

Maximum length: 18 cm (7 in)

Minimum aquarium size: 285 L (75 gal)

Lighting: Moderate to dim.

Water: Marine 22 °C (72 °F) - 27 °C (81 °F)

General swimming level: All levels.


Omnivore. They will pluck plankton-type foods from the water column and should be offered a varied diet of enriched adult brine shrimp, mysid shrimp, reef plankton, and color-enhancing rations. These active fishes should be fed at least two and preferably three times per day. They will also browse on filamentous algae growing on hard substrates.

Aquarium Compatibility

Generally peaceful, but male swallowtail angelfishes and larger females may chase small, docile planktivores such as anthias, fairy wrasses, fairy wrasses, Chromis damselfishes, and fire gobies.

Safe with stony and soft corals and Tridacna clams, although there are reports of Xenia and Anthelia corals being nibbled.

Special Care

This genus does not always ship well and may suffer from decompression maladies that affect its ability to maintain a stationary position in the water column. Avoid any fish that assumes a headstanding posture, that has tattered fins or redness on the skin or fins.

These fish may adapt better to lower light situations, as they are often collected in deeper water.


Spawning events may occur in large aquaria. Eggs and larvae are pelagic and not destined to survive in a typical aquarium without expert husbandry.


Males of this species are sometimes sold as "Zebra Angelfish," while the plainer females may be labeled as "Swallowtail Angelfish." The common name "Blackspot Angelfish" refers to a black area on the breast of male fish.

Reference: Reef Fishes Volume 3
Image credit: SWM
Text credit: SWM