Blue coral or Heliopora coerulea is a coral. It is the only species in the family Helioporidae and the only Octocoral known to produce a massive skeleton. This skeleton is formed of aragonite, similar to that of scleractinia. Individual polyps live in tubes within the skeleton and are connected by a thin layer of tissue over the outside of the skeleton. It is a common member of shallow coral reefs and is found extensively throughout the Indo-Pacific including Ryukyu Islands in southwest Japan, Coral Sea in northeast Australia and American Samoa. The largest blue coral colony in the world is thought to be off of Ishigaki Island of the Yaeyama Islands, in southwest Japan.
Due to its unusual blue colour and being fairly tolerant of conditions it can be used in tropical aquariums.