The Moorish Idol tends to be very peaceful. Due to its size, schooling nature, and need for swimming space, it requires a large aquarium of at least 125 gallons. As its beauty is most evident while swimming, giving it adequate room is well rewarded. It is compatible with most fish and larger invertebrates, but should not be kept with any polyps or corals, which it will eat. Small invertebrates may be threatened as well.
The Moorish Idol is a very difficult fish to feed. Live rock with large amounts of algae and sponges on which it can feed will help it acclimate. Then offer a varied diet of finely chopped meaty items, mysis shrimp, vitamin-enriched brine shrimp, Spirulina, and algae. It should be fed several times a day.
Source: Live Aquaria - Photo used as indicative only.