Richard E. Strassberg earned his Ph.D. in East Asian Studies from Princeton University.
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, granular or spiny, and is covered with overlapping plates.bout 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, 6,000 m (20,000 ft) below the surface.
Starfish have five or more (in some species) arms that radiate outward from a central body disc. The upper-side of their body can be smooth, bumpy or spiny. The mouth of starfish is located under the central body disc and tube feet line the bottom side of the arms.The tube feet enable the starfish to move using a hydraulic system, also known as a water vascular system. Most starfish are bottom feeders.Starfish are often brightly colored animals.he mouth of starfish is located under the central body disc and tube feet line the bottom side of the arms. The tube feet enable the starfish to move using a hydraulic system, also known as a water vascular system. Most starfish are bottom feeders. Starfish are often brightly colored animals.