Please ID these purple stems on my LR

[GjB]

These purple polyp looking soft stems (all purple) came with my Caribbean LR. Since I snapped this pic, they have spread and grown like crazy. They shrink a bit at night and open up for the light.

Any idea what they are and if they are harmless or not (they are quickly taking over my tank)? Are they just your basic harmless polyp? Sorry for the dark photo.

Thanks in advance

 

[GjB]

I'm a noob so please take it easy on me

I don't know how common these things are because in all of my image searching, I couldn't find anything. Not sure what term(s) to search for

 

[Misled]

Lucky you. They look like zoa's. The colors will show as they fully open up, but they will most likely be the common brown or green. Still a good find.

 

[scuba-al]

Yes, they look like zoa's. This is a very lucky find, coral coming in on live rock is relatively uncommon. If you don't like the look, you may want to seperate this rock from the rest of them, as the zoa's will continue to spread. Or, you may want to allow them to spread, and then frag. It's up to you. Either way, it's a lucky find. Good luck!