What's growing on my rock?
 

Can anyone tell me what these pink/clear thingys are on my live rock?

http://i610.photobucket.com/albums/t...9/DSC02574.jpg

I think they might be sponges.

purple lumps growing on rock
 

i believe these are tunicates except yours look much nicer than those growing in my tanks.

Sea squirts....tunicates.

I have these aswell.

Pineapple sponges. Pretty much all tanks will get them, especially in overflows, sumps, and filters. They are beneficial filter feeders.

I'll vote for tunicates as well. I belive that the pineapple sponges have only 1 primary hole and they look more prickly, while the tunicates always have 2 primary holes and look glassy. My completely non-educated opinion only.

What function do tunicates have? Are they good, bad or neutral?

Key Equine, judge for yourself - this is a good photo of a Pineapple Sponge. Is this what you have?

http://www.mikesreef.com/images/crit...tchhiker14.jpg

They look like tunicates to me. They have an incurrent and outcurrent syphon.
They are filter feeders and should not cause any problems in a tank. I've actually purchased larger species.