Genicanthus bellus is a deep-reef swallowtail angelfish from the eastern Indian and Pacific oceans, and it ranks among the most strikingly dimorphic members of its genus. Females wear a pale iridescent blue-white base broken by black, white, and blue striping that shifts from horizontal to vertical as it approaches the head, accented with yellow-orange markings along the dorsal region. Males trade that pattern for a softer palette of pale blue-gray crossed by horizontal blue, yellow-orange, and tan bands. Both sexes share the tapered, forked swallowtail silhouette that makes the genus so recognizable in motion, and adults reach roughly 7 inches. Wild fish occupy outer reef slopes and steep drop-offs, where they hover in open water and gather in harems.

Adult housing should be a mature, well-established marine system of at least 125 gallons, with length and open water taking priority over decorative density. Arrange rockwork to create caves, cracks, and shaded overhangs for retreat while leaving the upper water column clear for continuous cruising, since this fish spends most of its time swimming rather than picking at the substrate. Currents on its native slopes are swift, so moderate-to-brisk circulation suits it well. Because specimens are collected from depth, dim lighting during the first weeks eases the transition, after which most individuals adapt to standard reef intensity. A secure lid is worthwhile, as startled angelfish can jump.