Freshwater demoiselle　／　Blue ribboned demoiselle

Distributed across the Indo-Pacific. In Japan, from Okinawa Island southwards. Reaches 8 cm in length. Inhabits the brackish waters of mangroves and estuaries. Its body is deep blue, and its cleaved tail fin and dorsal fins have yellow bands. This species and the regal demoiselle (Neopomacentrus cyanomos) are the only damselfish that live out their lives in brackish waters.