The Small-spine Sea Star is very common on grass flats and in mangrove estuaries in the Western Atlantic, Gulf of Mexico, and the Caribbean Sea. It has five legs and can grow to a max of about 6 inches across. The larger disk just off center of the center of the starfish is called a madreporite and is used by the starfish to draw water into its vascular system. The orange tubes on the bottom of the starfish allow it to move while tiny organs eye spots at the end of each arm allow it to see.