🐠 Masked Swallowtail Angelfish (Genicanthus semifasciatus)
A Bright Yellow-Orange Face in Males, Creamy White in Females • An Elegant Crescent Swallowtail • A Rare, Reef-Safe Angelfish
 
📋 The Masked Swallowtail Angelfish, also known as the Japanese Swallow Angelfish or Tosayakko, displays a sexual dimorphism: males show a bright yellow-orange face and frontal body with narrow black vertical bars running down the length, while females have a creamy white-to-yellow body with a dramatic black band over the eye and along the tail. Both sexes share the elegant crescent-shaped "swallowtail" that gives the genus its name.
It comes from rocky reefs in the Northwest Pacific, from southern Japan to the Philippines, rare, collected from meaningfully deep water and, in some areas, from protected zones where collection is restricted, which is exactly why it commands such a premium price. Every Masked Swallowtail Angelfish we ship is feeding well.
Like other Genicanthus, it's considered one of the few truly reef-safe angelfish in the hobby, feeding predominantly on zooplankton rather than corals; it won't nip at soft or stony corals or sessile invertebrates. That said, it may occasionally pick at smaller planktivorous tankmates like fairy wrasses, flasher wrasses, or firefish that compete for the same food. Hardy and adaptable once settled, it readily accepts aquarium fare and is best kept singly, as a mated pair, or in a small harem of one male with several females, never house two males together, as this leads to serious aggression. It reaches up to 21cm, so plan on at least 470L.
 
💡 Highlights
🎨 Striking Sexual Dimorphism: Males and females look distinctly different
🌿 Reef Safe: One of the few truly reef-compatible angelfish species
💎 Rare: Collected from deep, sometimes protected waters
😌 Peaceful: More docile than most angelfish, may occasionally chase small planktivores
👫 Naturally Forms Harems: One male with several females in the wild