White polyps growing in dark spots

[Wildheart]

There were a few behind a rock,which lately disappeared.Now,there are hundreds in the back of my aquarium,behind the black wall hiding the skimmer and filtration devices.
They look like white tiny barrels,with tentacles at the end of a small mouth.They are not corals.I can't take photos because of the darkness.They only grow in dark places.
HELP :shock:

 

[Wildheart]

Did some research,I think they are Q-tip or pineapple sponges.Phew!Harmless!

 

[14 gallon nanocube]

cool keep an eye them after all spongebob squarepants lives in a pineapple sponge

 

[Wildheart]

:^::mrgreen:

 

[ErinCahir]

I love mine!

 

[parrotchute]

Yeah, Wild, they're a good sign you've got a healthy reef. They're filter feeders and will help process nutrients.

 

[Wildheart]

In the first room of the back pannel,they are brown and dusty,second room they are whiter,and third room almost pure!:D