White growths on live rock?

[yonsu]

I tried to research this but couldn't come up with anything similar. I've got these white growths popping up all over one of my pieces of live rock. They seem to have shown up over the span of just a few days, unless I am just not very observational. They look like white blobs or cylinders (they vary slightly in shape), they are not smooth, and at the end they have a fan or funnel-like shape that sticks out (narrow to wide from base to tip). I can actually see inside of them as well, as if they are hollow. I tried to get pictures, but my camera unfortunately sucks. Any input?

edit: BTW, I meant to say "white!"

 

[Fishfriend1]

could be sponges or Coraline algae, prob not a problem. If you can see inside them they that almost guarantees that they are sponges. Sponges are hollow filter feeders and will not hurt fish, but can crowd out corals.

Dont forget that pics, no matter how bad, are always helpful.

 

[Catpicklesdog]

They sound like pineapple sponges to me - harmless. I have loads of them but there are pictures in this link that may help you with an I.D

Ps amended the title for you

 

[yonsu]

Brilliant! Yes, they are pineapple sponges. Someone actually told me they were spirorbid worms at first, but nothing I could find about them seemed to be consistent with what I actually observe in my tank... No wonder. Thanks a lot!

And thanks for the title fix, Catpicklesdog