What are these??

[Jont82]

What are these growing on my rock?

 

[mr_X]

Q-tip or pineapple sponges.

 

[Jont82]

Cool thanks. Looked up about them and seem to be a good thing. Appreciate it!

 

[RainSalt]

I have a ton of these in my filter and could never take a decent picture to figure out what it was! Now I know what these are! =D