Originally identified as Fire Coral, I was later informed that this is Distichopora sp. From an article by Brad Ward, this coral grows primarily in cave structures of the reef and is non-photosynthetic. Amazingly, the color goes through the entire skeleton even though it grows in complete darkness. I put this piece in a cave structure of my tank but it didn't do well, so I moved it out into the open where it would get better flow. I never saw any extended feeding polyps, day or night. Unfortunately it was soon overgrown with coralline algae and died. This is one coral we don't know enough about to keep in captivity, I believe.