Good or bad anemone

[stevedog]

Just set up a new tank(2 weeks). Added live rock. Been reading books / magazines etc and they mention "glass anemone" which it seems are not good. All sorts of life appearing on the live rock including quite a few things that are stalks with what appear to be tentacles on top and also a few things that look like very fine white thread again with fine tentacls on the end.
Are the first ones glass anemones. If so do I need to get rid and if so how.
Any ideas about the other things.
Hope the descriptions help

[Gealcath]

Glass Anemones are Aiptasia, as in they fracture real easy like a glass window and spread everywhere in a short amount of time. They are usually Brownish in color and look alot like whats called the Curley Cue Anemone.

[dagunk]

The easist and cheapest way to rid yourself of them is getting a syringe (you can get them at most pharmacies for a nominal fee without a prescription) and some lemon juice. You then inject the syringe into the base/neck of the aiptasia. It's tricky, because they withdraw, so it may take a while until you're proficient. The other downside is they need to be a certain size before you really can have enough of a target. Worked GREAT in my FOWLR. :dance

http://saltaquarium.about.com/cs/msubpestaiptasia/a/aa061903.htm