Brown banded anemone (Arachnanthus nocturnus). Anemones have an array of tentacles which act as a defence mechanism and as a means of capturing plankton. When the tentacles are triggered they release a poison into the predator or prey. This tube-dweeling sea anemone inhabits shallow waters in the southern Carribean Sea. It is nocturnal. Photographed in Bonaire, Netherlands Antilles.