Pest on rocks

[Dustin2]

I have been trying to get rid of these flower like pests on my rocks and they have done nothing but multiply rapidly. Here is a picture. I am trying to figure out how to get rid of them and what they are.
http://picasaweb.google.com/lh/photo/C0vvt1e-IJg18C3A61M7Cg?feat=directlink

 

[chimmike]

looks like aiptasia to me. or hydroids.

 

[billsreef]

Hydroids. Real pain to get rid of. Best luck I've had is with a nice thick layer of kalk past that is left to sit with the pumps off for about a half hour or so.

 

[Floowid]

I had some of those come in on a coral rock. They starved themselves out without my intervention, or they could have been destroyed by my Sixline wrasse - I saw him nip at them a couple times. Had they not, I was ready with the kalk paste.