algae or seaweed?

hi i got these on my live rock, are they benign or should be removed?

 

Not sure on an ID on this algae. If someone else doesn't chime in with an ID on it then John at Reefcleaners.org should be able to.

 

maybe one of the caulerpa vickersiae variations, I think caulerpa vickersiae var furcifolia looks promising. Probably should be removed, looks like it is difficult to prune from the holdfast configuration (matting and fragile/thin), so if it spreads it can be an issue.

 

i had a clump of this and even my foxface wouldnt touch it i physically removed it of it and it hasnt come back

 

ok so better dry this rock before it infests others, thanks all

 

how long have you had that rock? did it just start to grow? and what's the growth rate of the algae?

 

i donno the age of this rock since i got it on craigslist from another aquarium and it already had the algae on it. i tried pulling them out but their roots are deep in the rock cavities. i saw a new colony of the same algae in another spot on the same rock it was easier to remove.
btw, it looked black and dead b4 i pulled out some to find the green color closer to the roots. now the black tips are coming back.