The red star fish has a small central disk with five arms (on very few occasions six or seven), long and relatively narrow. It is bright red in color. The needles, 1.5 mm, sometimes stand out from the skin.
Its maximum size is 25 to 30 cm.
It behaves in a solitary manner, does not form groups and the animals appear alone.
The stars are omnivores and eat mollusks and ofiüres, plants and carrion. They easily open the mollusks with their ambulacra legs and instead of ingesting their food and having internal digestion, they can bring out their stomach, wrap up their prey and dissolve it with the gastric acids; in other words, perform an external digestion and then absorb the result.
There is generally sex separation and they give off sperm and ovules in the sea. There is no sexual dimorphism, that is, we are unable to distinguish males from females. There may exceptionally be sexual reproduction by division.
We can find them on the littoral, on rocky beds up to 200 m in depth, and sometimes in fields of Neptune grass among the rhizomes.
In the event of danger, the star can release part of its body and regenerate it later; therefore, while predators are distracted with this part, the rest of the star can flee. This ability is called autotomy.