Blue Damselfish

Blue Damselfish (Chrysiptera cyanea)

The Blue Damselfish is likely the top-selling marine fish in the United States. Beginners appreciate its hardiness and compact size, while experienced aquarists admire the vibrant color and lively nature of this Pomacentridae family member. Female Blue Damselfish are entirely blue, while males feature an orange tail, earning them the names Orangetail Blue Damselfish or Blue Devil Damselfish. Native to reefs across the Indo-Pacific, Chrysiptera cyanea is typically seen defending a small territory. Interestingly, when threatened, the Blue Damselfish can darken to nearly black by hiding in a hole or crevice. Once the danger passes, it can return to its striking electric blue hue within seconds.

Somewhat aggressive by nature, the Blue Damselfish thrives in aquariums large enough to house multiple individuals comfortably. It’s an excellent choice for beginners and makes a great companion for saltwater tanks over 30 gallons. This species also fits well in reef aquariums with invertebrates. As it matures, the Blue Damselfish may exhibit more territorial behavior, especially towards new tankmates. If housing it with other damselfish, ensure the tank has multiple hiding spots to reduce aggression by breaking up territories. Its diet should include flaked and frozen foods, along with herbivore-specific preparations.