Bohadschia marmorata

The brown sandfish, or chalky cucumber, is a sea cucumber from the Holothuriidae family that inhabits the shallow seabed of the Indo-Pacific. Its tough, leathery body wall is rough with calcareous spicules and covered in translucent papillae up to a centimeter across, plus a few short spines. Reaching about 35 centimeters long, it has a cylindrical shape with a narrowed front end bearing a mouth ringed by retractile tentacles, and a rounded rear end with an anal opening. The cloaca, connected to the respiratory tree used for gas exchange, can eject defensive white sticky threads (cuvierian tubules) when the animal is stressed.

Its cream or orange body is partially obscured by dark brown speckles and blotches, with a wide pale stripe and many short, slender tube feet with knobbly tips on the underside. Found from the Red Sea and east Africa to Japan, the Philippines, and Australia, it lives on sandy or gravelly bottoms and in seagrass meadows down to about 36 meters, often half-buried in sand. As a detritivore, it moves using its tube feet and scoops sand, mud, and debris into its mouth with its tentacles, processing the material and leaving a characteristic trail of sand behind.