Azure Damselfish Identification Guide

Key identification features

• Small, deep-bodied damselfish reaching about 6 cm (2.5 in)
• Vivid electric blue covering the head, back, and front half of the body
• Sharp color break to bright yellow on the rear body, tail base, and caudal fin
• Faint dark bar sometimes visible through the eye
• Single continuous dorsal fin and a lightly forked tail

Common look-alikes

• Allen's Damselfish: also blue-and-yellow, but shows a thin black stripe along the dorsal fin base and a less abrupt color transition
• Yellowtail Damselfish: overall blue body, but the yellow is limited to just the tail fin rather than the whole rear half of the body
• Blue-green Chromis: lacks any yellow patch entirely and has a shallower, less contrasted forked tail

Where you'll see one

Azure Damselfish shelter among branching coral heads and rubble on shallow lagoon and outer reef slopes throughout the tropical Indo-Pacific, usually in small loose groups just a few meters below the surface. They retreat quickly into coral branches when threatened, so patient, quiet observation gives the best view of the full color pattern.