Yellow tube sponge (Lat. Aplysina aerophoba). Its depth range is from the lower intertidal zone to about 20 m (70 ft), usually being found in sunlit locations. It is a yellow, tube-forming or encrusting sponge which forms colonies up to 1 m (3 ft) across of irregular, yellow, tubular processes. The surface is slippery to the touch and the texture is firm and rubbery. When removed from water, this sponge turns blue, leading to its specific name “aerophoba” (Greek: “fear of air”). This sponge feeds by drawing water in through small pores known as ostia at the base of the sponge and ejecting the water from the oscula, having filtered out organic particles such as bacteria, unicellular algae and tiny particles of detritus.