Starfish Starfish Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or "basket stars". About 1,500 species of starfish occur on the seabed in all the world's oceans, from the tropics to frigid polar waters. They are found from the intertidal zone down to abyssal depths, below the surface. Starfish are marine invertebrates. They typically have a central disc and five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth,
Common starfish mass strandings have occurred in Britain and elsewhere at such places as Holkham Beach in Norfolk in 2009, near Sandwich in Kent in 2008, and near Brighton ten days later. A similar occurrence occurred on the shore of the White Sea where vast numbers of starfish came ashore on a nine-mile stretch of beach in 2004. It was said that people could not "walk around them because the whole shore was full of starfish". Russian experts expressed mystification as to the cause of the stranding. Common starfish The common starfish or common sea star ("Asterias rubens") is the most common