Allen's Damselfish

Allen's Damselfish is a breathtakingly vibrant species that showcases one of the most electrifying color gradients of any small reef fish. Its body transitions from a brilliant neon blue on the head and anterior portion through shades of electric blue into a rich, glowing yellow-orange on the posterior body and tail. This seamless gradient of saturated color, combined with its small size and active swimming behavior, makes Allen's Damselfish one of the most visually impactful fish available for small and medium-sized reef aquariums.

In the wild, Allen's Damselfish has a relatively restricted distribution centered around the Andaman Sea and Eastern Indian Ocean, where it inhabits coral-rich reef slopes and patch reefs at moderate depths. It is typically found hovering in small groups near branching Acropora and Pocillopora coral formations, darting in and out of the coral branches to feed on passing zooplankton and retreating into the coral structure when threatened. This close association with live coral in the wild translates to an appreciation for complex aquascaping in the aquarium, where it will establish territories around branching structures.

Allen's Damselfish is an excellent choice for beginner aquarists who want stunning coloration in a hardy package. It is exceptionally disease-resistant, eats readily, and adapts quickly to captive conditions. Like most damselfish, it can display semi-aggressive territorial behavior, particularly toward conspecifics and similarly sized fish, but this is considerably less intense than the notorious aggression displayed by larger damsel species. In appropriately sized tanks with sufficient rockwork, Allen's Damselfish integrates well into community reef setups. Named after the renowned ichthyologist Gerald R. Allen, this species honors a scientist who has described more reef fish species than any other living researcher.