please identify

[Jereli]

can someone please identify what this green plant thing is that is growing on the rocks. Its just growing out of no where.

 

[200 gallon reef]

I actually had a few of those come out of one of my rocks. They hung around for about 2 months and then dissappeared.

 

[Flreefer]

First pic looks like Caulerpa Racemosa Var. Peltata, the taller ones with the small flat tops.
Second pic, piece coming out of the rock on the left, looks like Caulerpa Ashmeadii.

 

[Jereli]

thanks. I was thinking where along those lines. now the question is.. should I remove this out just let it be? also..how does this get introduced into aquariums? this tank has been running little over year and never seen any signs of it.

 

[carey]

Looks like Bryopsis pennata and B. plumosa.

Here is the link for the information on it, I just had some and it was a pain to get under control. Most critters don't eat it cause of the taste so you'll have to get at it manually.

Nuisance Algae ID Guide