Non-stony hard corals is a term you might see,
which refers to hard corals that are not
"reef builders." Though, Heliopora may
border on an exception. These are kind of
odd ball, unique types of corals. The Tubastrea
types are usually cave dwellers that only open at
night, usually need hand feeding and are not
for beginners. Organ Pipe is an excellent,
easy-to-keep starter coral, plus it has that
pretty skeleton. Heliopora is easy to keep,
but harder to get. Distichopora is another
non-photosynthetic cave dweller, but easier
to keep than Tubastrea.