Common starfish Common starfish The common starfish or common sea star ("Asterias rubens") is the most common and familiar starfish in the north-east Atlantic. Belonging to the family Asteriidae, it has five arms and usually grows to between 10–30 cm across, although larger specimens (up to 52 cm across) are known. The common starfish is usually orange or brown, and sometimes violet; deep-water specimens are pale. The common starfish is to be found on rocky and gravelly substrates where it feeds on molluscs and other benthic invertebrates. The common starfish normally has five arms, broad at their base and gradually tapering to
Reef starfish or three months of their placement, while the mussels expanded within six months to cover 20-30% of the low zone when "S. australis" was removed. Without their predation, the mussels overwhelmed the area, threatening biodiversity. The juveniles of the species are detritivores. Reef starfish Reef starfish (Stichaster australis) is a species of starfish found in the South Pacific Ocean around New Zealand. A keystone species, the carnivorous starfish plays an important part in reducing the expansion of mussels. "S. australis" is pink or purple in color, with 11 arms. Found throughout New Zealand, "S. australis" is a keystone species in