Blue Damselfish

The Blue Damselfish, often called the blue devil or sapphire devil, is a small, vividly colored damselfish (family Pomacentridae) in the genus Chrysiptera, common across the Indo-Pacific. Its intense electric-blue coloration makes it one of the most recognizable and popular small reef fish in the aquarium trade. Despite its diminutive size, it is known for a feisty, territorial temperament typical of many damselfish. Wild populations are abundant and widespread across shallow reef habitats, and the species is not considered at risk.

• Small, oval, laterally compressed body
• Brilliant, uniform electric-blue coloration in most individuals
• Males often show an orange to yellow patch near the tail base and along the rear body
• Forked, slightly rounded tail fin
• Single continuous dorsal fin running the length of the back
• Reaches about 6-8 cm; females and juveniles are typically paler and lack the orange marking

Distinguished from similar blue damselfish by its small size, deep blue tone, and male's orange tail-base patch.

Blue Damselfish inhabit shallow coral reefs, lagoons, and reef flats throughout the Indo-Pacific, from East Africa to the western Pacific islands. They are typically found at depths of 1-12 m in warm, clear tropical water, often around branching coral heads, rubble, and rocky outcrops that provide quick refuge. They rarely venture far from shelter, darting into crevices at the first sign of a predator or disturbance.

This damselfish feeds on a mix of zooplankton picked from the water column and algae grazed from nearby rock and coral surfaces. It is highly territorial, especially males, which aggressively defend small patches of reef against intruders many times their size, including divers. Blue Damselfish are commonly seen in loose social groups around a shared coral head, with a dominant male often controlling the best territory. During spawning, males prepare a cleared surface where females deposit adhesive eggs, which the male then guards and fans until hatching.