Brown Tube Sponge (Agelas conifera) with a Sponge Brittle Star (Ophiothrix suensonii) inside. The Brittle Star can shed its legs if disturbed and replacements grow in place. They feed on planktonic foods and live in close associations with sponges. The Brown Tube Sponge can grow to 1 m (3 ft. 3 in.) and is common on the reefs of the Caribbean. Photographed in Grand Cayman.