Habitat: Inhabit most reef enviroments and are often the predominant coral between 40-100 feet. Polyps are generally retracted during the day, but extend prominently at night. Distribution: Caribbean Natural History Notes: Polyps feed nocturnally. Characteristics: Colonies usually form massive boulders and domes, but occasionally develop into plates or sheets, especially in deep water. Surface is covered with distintive, blister=like coralites. Shades of green, brown, yellow-brown and gray. Occasionally fluoresce red or orange.