Keyhole angelfish

About

The black angelfish (Centropyge tibicen) goes by another name, the keyhole angelfish, and once you see that small white oval patch against its deep, dark body, the reason becomes obvious. This is the largest species in the Centropyge genus, which sets it apart from most of its smaller cousins in the dwarf angel group. In the wild it ranges across a broad sweep of the Western Pacific and parts of the eastern Indian Ocean, turning up in lagoon environments and along seaward reef slopes where coral meets rubble. It tends to be on the uncommon side, particularly around isolated oceanic islands. Like most centropyge angels, it grazes heavily on algae, so a tank with established live rock and good algae growth will keep it far happier than a bare setup. In the wild these fish live in small harems of several individuals, though in the home aquarium they are typically kept singly or as a proven mated pair. They can be territorial with other dwarf angels and occasionally nip at coral polyps, so some thought goes into tankmate selection. This is a solid intermediate-level fish. Not overly delicate, but not the most forgiving species either, especially when first acclimating.