Habitat: Marine, reef-associated. Juveniles often found on Thalassia beds. Natural History Notes: Reported to secrete a mucus envelope at night. Feeds during the day, commonly over sand, occasionally over reefs. Grinds up what appear to be helpings of bare sand bottom. Presumably small organisms in the sand provide some nutriment to the fish. Have also been observed to eat filamentous algae Reported to reach 3 feet. Forms large spawning aggregations. Depth: 3 - 25m Characteristics: Adults : deep or greenish blue overall. Distinct hump on the forehead in profile. Three rows of scales below the eye on the cheek. Juveniles : yellow area on top of the head extending back to foredorsal fin. Have the mouth set lower, the snout blunt and more prominent than other parrotfishes before they acquire the hump on the forehead.