Sea anemones are among the most beautiful invertebrates of the coral reef. Like delicate undersea flowers nestled among kelp, they trap small fish by paralyzing them with venom from their tentacles. Sea anemones are common on rocky coasts and coral reefs around the world.
The bodies of anemones are tubular; they may be thick and short or long and slender. The columns vary in size from only a fraction of an inch to a foot or more in diameter. They also vary in color and texture, from creamy white to bright pinks and yellow with a leather-like surface to a rough warty brown appearance. Their mouths are at the upper end of the bodies surrounded by rings of tentacles made up of stinging cells (nematocysts) that paralyze their prey. The tentacles then contract and guide the victim towards the mouth. A jelly-like substance inside the body of the anemone contains free moving cells for digestion and excretion, respiration, and reproduction. Some anemones excrete a sticky adhesive on the surface of their columns that becomes covered with bits of sand, shell, and assorted foreign objects.
Anemones use suction to attach themselves to hard surfaces like shell fragments, rocks, docks, and even hermit crabs. Some burrow into rocks, sand, or dead sponges. Anemones seldom move. They may change their position by a very slow tumble (head over heals) like a somersault, but usually they glide slowly or creep.
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