usually different colors. Oftentimes when
found dwelling in live corals, particularly
Porites, the worms extend their tubes at
about the same rate as the coral colony
adds on new skeletal material, so the
opening of their tubes end up staying pretty
much flush with the surface of the coral
colony’s skeleton. Thus, all you’ll usually
see of the tube is the spike and operculum
right at the surface, with the gills emerging
colonies, and not as the worms themselves.
These coral colonies are usually fist-sized
heads of Porites that contain several worms
that have their tubes inside their skeletons,
and nicely enough, the different worms are
Looking just below the gills, you can see this specimen’s operculum.
from the tube’s opening. But in some cases,
the entire tube can be seen, just under a
thin layer of coral tissue and skeleton.
Also note that these are sometimes called
“worm rocks” for some reason, instead of
“live stony coral with worms,” which is
very misleading for obvious reasons. The
coral colony will need very bright lights
and everything else that live corals require
to survive, meaning that such specimens
should only be placed in well-lit reef
aquariums if you expect them to live.
Still, there are occasional specimens that
really are on rocks/pieces of dead coral.
The biggest source for these is no more,
however. Many years ago, it was possible to
get pieces of live rock collected from Florida
waters that were absolutely covered with
Christmas tree worms, but the collection of
the rock has been stopped—although I’ve
seen a few on aquacultured live rock from
Florida, and on some hand-picked rock/
dead coral specimens from the Pacific. So
there’s a chance that you might be able to
come up with some anyway. For what it’s
worth, I don’t recall ever seeing any (alive)
on pieces of Pacific live rock being sold as
bulk rock, which is shipped damp rather
than in water.
Before you run out and look for a coral
head full of pretty worms, I have to tell
This specimen has retreated into its tube and is pulling its operculum shut. You can also see the
spike that protrudes from the opening.