Asterias rubens; Print; The common starfish; common sea star or sugar starfish (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.