White spiral things?

[Nitzanah]

Can someone tell me what these things are and if they're a problem? They're all over my glass and rocks.

 

[SammyL]

Not a problem, they are a type of filter feeder; I do not remember the name though.

 

[Sk8r]

spionids. Not really a problem, kind of neat. But they can stick your fingers if you're moving rock (a reason to wear gloves) ---fish like tangs will eat them.

 

[cloak]

Check this out. (Spirorbid)

http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml

HTH.