spiny starfish (marthasterias glacialis), starfish with a small central disc and five slender, tapering arms with spines

animal aquarium arms asteroidea background beach central cluster clusters coral disc echinoderm echinodermata echinoderms ecosystem environment feet fish glacialis habitat invertebrate invertebrates large life marine marthasterias nature ocean reef sand sandy sea seabed skeleton small spine spines spiny star starfish stars suction thorn thorns tropical tube underwater water wildlife