Of all the Hawaiian reef fish, the surgeonfish or tangs are the most plentiful and prominent. Included in this family is the closely related Moorish Idols. Although they resemble in appearance butterflyfish and they lack a scalpel, Moorish Idols swim largely with their pectoral fins. Most of the surgeonfish feed on algae, and their mouths scrape the surface of rocks and dead coral or they nibble on leafy seaweeds. Since algae grows best in bright light, most surgeonfishes enjoy the shallow waters. There are 23 species of surgeonfish in Hawaiian waters.
Moorish Idols have light gold bodies with black bands, long orange and white striped snouts, and graceful white filaments. They often swim in pairs, and occasionally in small schools. They are similar in appearance to the Pennant Butterflyfish, but they are not related. Immature Moorish Idols grow hornlike spines which later fall off. For that reason the species name means "horned." The Hawaiian name means "curves," "corners," "angular," and "zigzag." This name is applied to many fish including hammerhead sharks. They grow about 8 inches. .