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,
Stichodactyla toxin Stichodactyla toxin Stichodactyla toxin (ShK) is a 35-residue basic peptide from the sea anemone "Stichodactyla helianthus" that blocks a number of potassium channels. An analogue of ShK called ShK-186 or Dalazatide is in human trials as a therapeutic for autoimmune diseases. "Stichodactyla helianthus" is a species of sea anemone (Phylum: Cnidaria) belonging to the family "Stichodactylidae". "Helianthus" comes from the Greek words helios meaning sun, and anthos meaning flower, which corresponds to the species' common name "sun anemone". It is sessile and uses potent neurotoxins for defense against its primary predator, the spiny lobster. The venom contains, among other components,