Is this good stuff or should I pick it off? (on live rock)

[lil.guppy]

I know there is some dead stuff on my LV because I did not scrub it but I have noticed this green stuff is 'coming back to life' Is this good stuff? This is its 2nd day in the tank
http://c3.ac-images.myspacecdn.com/i...29922dc03a.jpg

 

[spanko]

Can't tell what it is, too small for me to identify.

 

[lil.guppy]

Here is one of the established pieces. It started dying off at the ends and making its way, but there are new shoots coming from the base.
They are only on this one rock.

 

[spanko]

Looks like it might be aCodium sp.. Could be invasive if not kept in check.