New to reef, what is this

[MysterioMask]

I just put live rock and dry rock and Coraline frags in my tank about 2 and a half weeks ago. I have these 2 green plant like things growing now. Are they something good, bad. Or something to remove asap?

 

[Sniperhank]

Macro algae...most likely caulerpa of some type. I'd take that piece out and scrape it off with an old toothbrush to prevent it from spreading. It can be quite invasive. If you can live without that chunk of rock in your tank, that'd be the safest bet.

 

[MysterioMask]

Macro algae...most likely caulerpa of some type. I'd take that piece out and scrape it off with an old toothbrush to prevent it from spreading. It can be quite invasive. If you can live without that chunk of rock in your tank, that'd be the safest bet.

It's actually growing on a small piece of coralline frag so I could actually cut it off with a knife and put it back in or just dump the whole piece

 

[Sniperhank]

If you can cut that chunk off, that'd be best and safest. Can also just scrub it off too, just outside of the tank of course.