Aiptasia ID and getting it out

My tank has just finished cycling and I noticed what I think is an aiptasia.
It is about 1/2" tall and has a 1/4" tube (I'm positive it's not a tube
worm), white/clear in color and attached to a small piece of white base
rock. I've read that usually they are brownish but didn't know if this
one just hadn't developed yet. Last night it moved about an inch from
it's first location after I turned off the powerheads for a cleaning.
Since then it has grown more arms. I tried taking a pic but it just
looked like a white blur since the anemone is clear and the base rock is
ultra white.

I still don't have my light canopy built yet, therefore, I cycled with no
light other than just room light and a little from a distant window. I
thought anemones needed a lot of light, but this one is located in the back
corner behind a larger piece of rock, nearly the darkest spot possible in
the tank. I have to use a flashlight just to see it in the daytime.

Now here is the question part. Should I go ahead and consider that this
is an aiptasia and destroy it or wait till it grows more and see? From
what I've read on message boards, everyone basically says that if it's a
hitchhiker anemone it must be bad, is that true? Secondly, since it is
attached to a piece of base rock that would be fairly easy to remove from
the tank, should I remove the whole rock and destroy it that way? I would
guess that if this truly is an aiptasia this isn't the only one in there, so
should I get a peppermint shrimp and let him do the job since the tank is so
new? I don't want something in there that will eat all the pods, I'm
saving them for a mandrin in a couple of years.

The only other critters in the tank are some pods, worms, snails and the
like. Nitrite is 0, Ammonia is 0, Nitrate is 4, ph at 8. tank is
36x18x24.

Thanks for any replies. Also thanks to all of those who post here as your
comments and suggestions have been of great help to me.

Darrin