Caulerpa sertularioides; caulerpa should never be allowed to make its way into the ocean, where
it can become a pest that outcompetes native species.
I am 15 and relatively new
to the hobby, but I currently
have a corner saltwater
aquarium with sand, live rock, a false
percula clown, a blue-green damsel, two
turbo snails, and a chocolate chip sea star.
I recently discovered two things growing
on my rocks: a tall green plant with
broad, fan-like leaves, and some tube-like arms with long, hair-like tentacles.
Could you tell me what each of these are,
as well as a little about them?
From your description I‘d
guess that the first “plant” you
mention is Caulerpa, which
has growth similar to what you
describe. It is quite common, but it is actually
illegal to keep in California because the
environmental authorities worry about more
infestation of this macroalgae in California
waters. (It has happened before.) One reason
that I had “plant” in quotes is that there are
not many true plants—vascular plants—that
grow in the ocean. Most of them are actually
macroalgae, which simply refers to the large
algae types. Incidentally, one example of
these macroalgae are the sea kelps that are
common in California. They look something
like vascular plants, but they have holdfasts
instead of roots.
I’m sorry to say that your other “plant”
sounds like it might be Enteromorpha, which