The Moorish Idol is colored with white, yellow and black vertical body markings. They are frequently found schooling along the reef and provided that you have a large enough tank, you may be able to keep multiples in your saltwater aquarium.
This is a very finicky eater and to make matters worse, their protruding mouths are sometimes damaged during collection and transport. Another good reason to use the quarantine tank when you first get them is to get them eating without any competition. In the ocean they graze on marine algae and sponges. Having copious amounts of live rock in your tank will provide grazing opportunities in between meals. Try to give them a varied diet of live or frozen marine fish foods.