Yellowtail damselfish

About

The turquoise-spotted demoiselle (Microspathodon chrysurus) is one of the Caribbean's most visually arresting damsels, and one of its most combative. Juveniles are almost impossibly pretty, deep blue-black bodies scattered with iridescent turquoise spots, and they spend their early lives tucked among the branches of fire coral and Millepora on shallow reef edges. As they mature, the spots fade and the tail transitions to a bright yellow, which explains the alternate name yellowtail damselfish. Adults stake out territories near the outer reef crest, particularly around caves, crevices, and patches of fire coral, which they'll defend with genuine ferocity against fish and divers alike. In the wild they feed mainly on algae, but they'll also pick at coral polyps and small invertebrates, and juveniles have been observed cleaning parasites off other reef fish. A surprisingly cooperative behavior for such an aggressive species. In the aquarium, this fish needs space and a well-established reef layout to feel at home, but its territorial nature means tankmate selection has to be thoughtful. It's not a beginner's fish, but for an intermediate keeper who plans the stocking carefully, it's a rewarding and long-lived resident with genuine reef character.