What is this?

[soonerzoo]

These white fingerlike things started growing out of my live rock , what is this?

 

[Aquarian]

It's a type of sponge, a harmless filter feeder. And pretty cool too

 

[salt_for_brains]

That is cool looking. I've never had one grow like that.

 

[Marinne13]

I have a rock covered in a sponge that looks like that...it grows fast but it kind of gets annoying as it smothers coral

 

[mariobrothersleeve]

Wow, that is awesome.