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
Crown-of-thorns starfish of a proportion of individuals with regenerating arms. A variety of about 11 species have been reported to prey occasionally on uninjured and healthy adults of "A. planci". All of these are generalist feeders and none of these, however, seems to specifically prefer the starfish as a food source. This number, however, is probably lower, as some of these presumed predators have not been witnessed reliably in the field. Some of those witnessed are: Gonads increase in size as the animals become sexually mature and at maturity fill the arms and extend into the disk region. The ripe ovaries and