rabbitfish, any of about 25 species of fishes constituting the family Siganidae (order Perciformes), found in shallow tropical marine waters from the Red Sea to Tahiti. They live in areas near shore or around reefs and graze on algae and other plants. Most rabbitfish are olive or brown in colour and have sharp, poisonous spines on several of their fins. They seldom attain lengths greater than 30 cm (1 foot).