Moorish Idol, Zanclus cornutus

The Moorish Idol, also known as the “crowned scythe” (Zanclus cornutus) is the sole representative of the family Zanclidae. This is a small perciform marine fish. The Moorish Idol is a native of tropical to subtropical lagoons and reefs. Throughout the Indo-Pacific, the Moorish Idol is noteworthy for its broad distribution. Numerous butterflyfish (all of the genus Heniochus) are similar to the Moorish Idol.

It has been suggested that the Moorish Idol received its name from the Moors of Africa, who seemed to believe the fish brought happiness. This fish is also a popular aquarium fish even though they are well-known for their short lifespans and difficulties thriving in aquarium environments.

Moorish Idols stand out with black, yellow, and white contrasting bands on their distinctively compressed, disk-like bodies. The dorsal fin has 6 or 7 spines that are dramatically elongated to form a tailing, philomantis extension -a sickle-shaped crest. The other fins of the Moorish Idol are quite short. The Moorish Idol has a small mouth at the end of a long, tubular snout. This fish has long bristle-like teeth which line the mouth. The eyes of the Moorish Idol are set high on the fish’s deeply-keeled body. The Moorish Idol adults have perceptible bumps that are located above each eye. The anal fin of the fish may have 2 or 3 spines. The Moorish Idol can reach a maximum length of 9 inches. With age, the sickle-like dorsal spines shorten.

Moorish Idols prefer flat reefs rather than their native of shallow waters. At depths ranging from 9 to 590 feet, Moorish Idols will be found in both clear and murky conditions. The range of the Moorish Idols extends from East Africa, Indian Ocean and the Ducie Islands, such as Hawaii, all of Micronesia and southern Japan; Moorish Idols are also found south of Peru to the southern Gulf of California.

The Moorish Idol consumes tunicates, sponges and other benthic invertebrates. Contained Moorish Idols tend to be picky eaters. Commonly, they will eat nothing and die or uncommonly, eat everything. Eating small portions of banana and avocado may be feed in captivity and eating a diversity of items is healthy.

Moorish Idols form pairs or sometimes small schools. They are diurnal, sticking to the bottom of the reef at night and adopting drab coloration. Moorish Idols mate for life. The juvenile are inclined to schools, like the butterflyfish. As the Moorish Idols turn into adults they become more aggressive towards one another.
Being pelagic spawners, the egg and sperm of the Moorish Idol are released in midwater and the eggs are fertilized and left to be carried away with the currents. The unusual long larval stage may explain the magnificent range of these fish. The fish can reach a length of 3 inches before becoming free-swimming juveniles. The developing larvae will have drifted considerable distances before this time.

These fish are known for their difficulty to maintain in captivity. Their fish tanks often exceed 200 gallons. They are unappeasable eaters and they are notorious for being destructive. They have a poor survival rate; most of them do not surpass a full year and those who do exceed a year die shortly after. It is considered cruel to keep these fish is captivity and nearly impossible to keep alive. Some aquarists prefer to keep similar species that resemble the Moorish Idol such as the butterflyfish.

In 2003 Willem Dafoe recorded the voice of a Moorish Idol named Gill in the Pixar film Finding Nemo. He was one of Nemo’s tank inhabitants. Moorish Idols are one of the most iconic of coral reef fauna.

Image Caption: Moorish Idol in Kona, Hawaii. Credit: Brocken Inaglory/Wikipedia (CC BY-SA 3.0)