Moorish Idol

The only surviving member of the family Zanclidae in the order Acanthuriformes is the saltwater fish species known as the Moorish Idol (Zanclus cornutus). The Moorish idol is renowned for its widespread presence in the Indo-Pacific. It is a frequent resident of tropical to subtropical reefs and lagoons. Many butterflyfish species (genus Heniochus) resemble the Moorish idol quite much. It is closely linked to the extinct Eozanclus brevirostris from the Middle Eocene of Monte Bolca, if not a direct descendent. The name of the Moorish idol comes from the Moors of Africa, who allegedly thought fish brought happiness. Moorish idols are a popular aquarium fish, but despite their availability in a variety of habitats and abundance, they are famously picky and difficult to acclimate to captivity.

Moorish idols are alluring to aquarium keepers because of their uniquely compressed and disk-like bodies, which stand out in contrasting bands of black, white, and yellow. Except for the dorsal fin, which has six or seven drastically enlarged spines that form a trailing, sickle-shaped crest known as the philomantis extension, the fish's fins are generally modest. Moorish idols have numerous long, bristle-like teeth lining small terminal mouths at the ends of long, tubular snouts. The Moorish idol is distinguished from butterflyfish by possessing a conspicuous, triangular-shaped black anal fin.