It all depends on what species is next to the other, and
what species is up current, and what species is bigger
than the other. Just like a snake can eat a frog, so also
a frog can eat a snake. That's a good reason to frag
corals, so that if one gets killed by another you still
have plenty more frags. It's interesting to see who will
win the battle. Sometimes an aggressive species will loose
the battle to a nonaggressive species because the
nonagressive spices is a faster grower.

What happens in the wild, is that a very diverse reef with
lots of species over time becomes fewer and fewer species,
until you have large reefs of just one species, then
something will happen to it and kill off large amounts of
the reef, and then a diversity of species will once again
grow there.

Wayne Sallee
Wayne's Pets



AL wrote on 1/13/2007 7:27 PM:
I have a 120 G reef tank started about 1 year ago. I have noticed that
my small purple mushroom corals will kill off Acropora, some zooanthids
will kill off other hard corals, some button polyps will not damage the
same hard coral, yellow polyps seem mellow with everyone, etc. I am
dealing with this by trial and error and enjoying it. However--are
there any general rules? Has anyone sorted out a general hierarchy of
who bumps off whom in the battle for territory? Thanks for your
comments.