Sea liliesCrinoidea

Crinoidea are echinoderms comprising two distinct adult forms: mobile feather stars and stalked sea lilies. Feather stars are recognized by their small, cup-shaped body disc, from which typically 10 to over 200 branched, feathery arms radiate, spanning up to 50 cm (20 in) in diameter. These arms are equipped with numerous small pinnules used for feeding. Their colouration is highly variable, including solid shades of black, red, orange, yellow, green, or white, often patterned with contrasting bands or spots. Sea lilies, conversely, remain anchored to the substrate by a permanent stem throughout their adult life.

Feather stars are frequently observed resting on hard corals, sponges, or rocks, inhabiting shallow reef crests to depths exceeding 100 meters (330 ft). They move slowly by crawling across surfaces or by brief bursts of swimming. Sea lilies are typically found on deeper reef walls and at the base of drop-offs, from 20 meters (65 ft) downwards. Both forms feed by extending their arms into the water column to filter plankton and suspended organic matter using their pinnules. Many crinoid species exhibit activity during both day and night.