Help with small coral ID

[stellaslane]

I'm struggling to figure out what is going on with these small polyps I have in my tank. When I first received my live rock, these rocks were once covered with beautiful green button polyps but sadly they all passed away over the years and left me with these small tube-like polyps. Recently I have moved tanks into a smaller one and added these polyp rocks. More of them seeming to become more active and maybe getting a little bigger? My questions are, are these what I think they are, very small green button polyps? I haven’t been able to find any pictures of polyps this small online. Or are they something completely different? And if they are, will they get any bigger? Thankyou any help would be great.

 

[Cell]

Colonial hydroids

 

[stellaslane]

Oh wow, thankyou! I had no idea. I know these buggers are pretty hard to get rid of, luckily they're only on smaller rocks I can remove. Is my best bet to let the rocks dry out for a couple months or is the boiling method better?

 

[Cell]

I'd never recommend boiling. I bleach rocks to reset. Outside. In a bucket.