Moorish Idol Fish (Zanclus cornutus)

Moorish Idol fish
Moorish Idol

Last updated on June 25th, 2022 at 02:15 am

The moorish idol fish (Zanclus cornutus) are deep-water marine fish that inhabit the waters of the Pacific Ocean from Japan to Australia and New Zealand, although they have also been found in deep-water habitats in the Atlantic Ocean as well as the Gulf of Mexico. These fish are fairly large, growing to about 9.1 inches in length, and have bright yellow bodies with black stripes. They prefer habitats near coral reefs, where they can find plenty of crustaceans and small invertebrates upon which to feed.

The moorish idol fish species has an oval-shaped body that’s pale brown to yellow in coloration with two dark brown bands on either side, and its head features two large eyes and two smaller ones, as well as a rounded snout and smallmouth that are filled with sharp teeth.

Origin and descriptions

The moorish idol fish, Zanclus cornutus, also known as the False Moorish Idol, is native to the western Pacific Ocean and Indian Ocean regions of the world, but has been known to be found in Hawaiian waters and even as far north as San Francisco. The common name comes from its similarity to the well-known Moorish idol cichlid in appearance and behavior.

Native to the Indo-Pacific region, the moorish idol fish thrives in warm, shallow water, and can be found from Australia to Japan and as far west as India.

Zanclus cornutus, also known as Moorish idol fish, is a relatively common species of wrasse native to coral reefs. It can be found from Sri Lanka, north and east towards Japan and Taiwan, in depths between 0.3 and 180 meters. They usually grow to about 7 inches long, but have been observed up to 9.1 inches in length.

Species profile

Moorish Idol fish

These types of fish belong to the family Zanclidae, which is comprised of more than 40 species of marine fish. This species is also known as Zanclus cornutus, and it’s a type of anglerfish that lives in tropical waters. It can be found in various parts of Australia, including Western Australia and New South Wales.

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In fact, some have even been spotted off of Lord Howe Island. The moorish idol fish has several physical characteristics that make it unique from other types of anglerfish.

Scientific name

The scientific name of the Moorish idol fish is Zanclus cornutus


The moorish idol fish lives in the Indo-Pacific region and typically inhabits deep reef environments with sandy bottoms between depths of 12 and 50 meters deep, with an average temperature range of 24 to 29 degrees Celsius.

Moorish idol size

Adult Moorish idol fish can typically grow to size around 7-9.1 inches (18-23 cm) in length.

Tank size

Due to their size, schooling nature, and need for wide swimming space, the minimum recommended tank size is 100 gallons (379 liters), but larger tanks up to 150 gallons (568 liters) are better.

Tank requirements

Moorish idol fish are native to Indo-Pacific waters and require saltwater tanks with plenty of vegetation. With a pH range between 8.1 and 8.4, they do best in a range of 78 to 82 degrees Fahrenheit, with a specific gravity between 1.020 and 1.025. They’re also schooling fish, so you’ll need at least six specimens for breeding purposes.

As far as tank mates go, moorish idols are peaceful, but their long pectoral fins make them vulnerable to nipping from larger fish. Because of their size, you should keep them away from aggressive species like lionfish or tangs.

They can also be sensitive to changes in water chemistry, which is why it’s important to monitor salinity and test your water regularly. You may want to think about adding a protein skimmer or other device that will help remove waste before it accumulates. Maintaining proper levels of nitrates and phosphates is crucial when keeping these fish; if there is too much ammonia present, they will not thrive.

Tank mates

This fish can be kept with other non-aggressive fish of comparable size. Good choices include angelfish, butterflyfish, and anthias.

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They can also be housed with cave-dwellers like dottybacks, carnivorous grazers suchs as wrasses, and non-aggressive species like Chromis.

A 250-gallon aquarium could house a pair of adult moorish idols as well as other species that inhabit similar habitats in nature, including groupers and other large species of surgeonfish.


Moorish Idol fish

Similar to its surgeonfish cousins, the Moorish idol is a pelagic species, which means it is a free-spawner or egg-scatterer fish that spawns in groups. Following the ejection of small eggs by the female, the male swims over and fertilizes the egg cloud as he goes. Many eggs are laid by the female in the spring and summer, usually hundreds at a time.

As soon as the egg is fertilized, it floats to the surface and joins the plankton stream, where the larva feeds and develops into a miniature adult.

Are they aggressive or peaceful?

Moorish idol fish are generally peaceful, but they may become aggressive if threatened or disturbed.

Moorish idol care

Moorish idol fish

The Zanclus can be cared for in a 100 gallon or larger aquarium with live rock and a sandy substrate. You should have plenty of nooks and crannies to hide away while they adjust to their new home. The tank should also be well-established so that water quality is optimal.

While they can adapt to lower levels of dissolved oxygen, doing so is extremely stressful for them and should not be attempted by new aquarists. A protein skimmer is recommended as it will remove organic wastes from your aquarium’s water column.

A sump or refugium would be beneficial as well since it provides an area where you can grow macroalgae and other marine vegetation which will provide a supplemental food source for your Moorish Idols.

What do Moorish idols eat?

The Moorish idol fish frequently pick soft coral polyps and large polypod stony corals. Despite this fish’s natural preference for coralline algae and sponges, there is no reason for it not to eat either other sessile invertebrates or crustaceans that move.

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Moorish idol fish

This fish species can live for 2-5 years.

Parasites and diseases

Moorish idol fish are prone to a number of parasitic and bacterial infections, making it important for an aquarist to keep them in high-quality water. Though not fatal, oodinium is a disease that can often be treated by removing and cleaning equipment with boiling water.

Popeye’s Disease is another ailment more common in moorish idols than other marine life due to their long lifespan, poor eyesight, and poor behavioral response to sickness. Symptoms include cloudy eyes and lethargy.


They can be preyed upon by sharks, tuna, and other large fish. If you see a Moorish idol fish with a missing tail or fins, it is likely that it was attacked by another fish. These wounds will heal over time, but they may leave scars.

They can also be attacked by large Tomato Clowns and Moray Eels.

Do they make good pets?

Yes, they make great pets. The Moorish idol fish is somewhat difficult to handle because of its small size and very active behavior, but a large tank can provide ample room for exercise. In fact, if you have any desire to have your Moorish idol fish swim around while you watch it, you’ll need at least a 100-gallon tank with plenty of live plants for cover and hiding places.