Zanclus cornutus

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See Talk:Zanclus cornutus for individual experiences with this species, Zanclus cornutus. Feel free to add your own personal experiences.

Common Name
Moorish Idol
Binomial Name
Zanclus cornutus
Zanclus cornutus 1.jpg
Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Zanclidae
Genus: Zanclus
Species: cornutus

Common Names

  • Moorish Idol



Information about the body shape, skeletal characteristics, how it appears, colouring etc.

Similar Species

May be confused with bannerfish such as H. diphreutes or H. acuminatus. These are ideal substitutes for this problematic fish.

Maximum Size

16cm [1]

Associated Organisms

Anything that lives in symbiosis, parasitic or opportunistically with it.


Usually in small groups, but occasionally in large schools. Feeds primarily on sponges. [1]

Captive Care

Tank Size

Active fish, therefore at least a 5 x 2 x 2 for adult fish.

Water Flow





Never buy a Moorish Idol that is not feeding at a shop, since some will not feed in captivity.

Natural feeding is believed to be sponges, algae and small crustaceans. In captivity however they have proven difficult to get feeding. During this period it is essential that the fish has a lot of live rock available to pick at it. This is another reason why larger tanks are recommended - there is more natural food for it.

Common food to try include :

Growth Rate

How quickly it will grow under various conditions.


Susceptible to assorted parasites and diseases that affect other wild caught fish.


These fish are largely free swimming fish, rarely hiding. Hiding is in fact a difficult prospect for a fish with such a large dorsal fin. The large fin has a somewhat free flowing piece at the end which can fall off easily. It is assumed this is used to distract any aggressors or predators while it flits away quickly. They are quick off the mark and able to change direction very rapidly.

The stress of being caught and transported is often too much for these fish, and most will not eat again. Those that are obtained through commercial collectors the fish can already have gone over a week without eating (or have even been fed).

Sometimes it is possible to find an Idol in LFS's that is already eating, even ravenously. This is great, however it is far from any degree of certainty of survival. Of those that survive the non eating period, most will fail after two months regardless. It is unsuitable for the majority of aquarists because some ingredient seems to be missing in the captive environment.

Long term survival (greater than 2 years) seems to rely on the aquarist to be able to able to provide a well balanced diet (and the fish to accept it). What this entails is unclear, however making a multitude of foods available is the best bet. Its is extremely rare for any of these beautiful fish to survive for this length of time in captivity. The Moorish Idol is not an aggressive fish, and will get on with any non aggressive tank mate. It will not likely respond well to any aggressiveness.




Does it have any fish that it should not be housed with?


Anecdotal reports suggest the fish may nip at fleahy corals


Does it have any invertebrates that it is not compatible with?


How it reproduces, how suitable it is to breeding or captive propagation, techniques on how to etc.

Local Ecology


East Africa to Mexico, north to southern Japan and Hawaii Islands, south to Lord Howe, Kermadec and Rapa Islands[1]


Ubiquitous around rocky and coral reefs from inner harbours and bays to seaward reefs as deep as 182m.[1]

Additional Information

Some additional notes on it that don't fit in the above sections.



  1. 1.0 1.1 1.2 1.3 (Lieske Myers 1996): Lieske, E., Myers, R., Coral reef fishes : Caribbean, Indian Ocean, and Pacific Ocean : including the Red Sea, Princeton University Press: Princeton, 1996.