The Moorish Idol (Zanclus cornutus) is a species of marine ray-finned fish belonging to the family Zanclidae. It is the only member of the monospecific genus Zanclus and the only extant species within the Zanclidae. This species is found on reefs in the Indo-Pacific region.

Distribution and Habitat

The Moorish Idol has a wide range in the Indian and Pacific Oceans. It is found from the eastern coast of Africa between Somalia and South Africa east to Hawaii and Easter Island. It is also found in the eastern Pacific from the southern Gulf of California to Peru, including the Galapagos and Cocos Island. It lives between depths of 1 and 180 meters in turbid lagoons, reef flats, and clear rocky and coral reefs.

Physical Description

The Moorish Idol has a highly laterally compressed and disc-like body with a tube-like snout and small bony protuberances above the eyes in adults. The mouth is small with many long bristle-like teeth. The dorsal fin is supported by 6 or 7 spines which are elongated into a long filament resembling a whip, and between 39 and 45 soft rays. The anal fin contains 3 spines and between 31 and 37 soft rays. The maximum published total length is 23 cm (9.1 in), although 21 cm is more typical. The body has a white background color with two wide black vertical bands and a yellow patch on the posterior end. The caudal fin is black with a white margin.

Diet and Feeding

Moorish Idols mostly feed on sponges, with sponges making up about 70 percent of the total weight consumed. They also feed upon algae, coral polyps, tunicates, and other benthic invertebrates, making them somewhat omnivorous. In captivity, they are notoriously picky eaters and may refuse food entirely or eat voraciously.

Behavior and Reproduction

Moorish Idols are normally found in small groups of 2 or 3 individuals but can also be solitary or gather in large schools. They are pelagic spawners, with males and females releasing sperm and eggs into the water. The larvae have a specialized long pelagic life stage, which contributes to their wide geographic distribution.

Aquarium Care

Moorish Idols are notoriously difficult to maintain in captivity. They require large tanks, often exceeding 100 gallons. They are voracious eaters and can become destructive. In captivity, they are typically very picky eaters and may either refuse food and perish or eat everything at once. They are recommended for expert aquarists only. They can reportedly live for up to several years in captivity with proper care.

Conservation Status

Classified as Least Concern by the IUCN Red List. The species is widely distributed and locally abundant with no major threats identified.