Any idea what these are?

[drewsreef]

Hi guys! Today i was rescaping my tank and noticed my rocks were sprinkled with these white fluffy cone looking things. Idk if they're sponges or what they are? They come off easy and are soft.

 

[ISpeakForTheSeas]

Pineapple sponges - harmless filter feeders. They tend to boom then bust in population before going away on their own.

 

[drewsreef]

Pineapple sponges - harmless filter feeders. They tend to boom then bust in population before going away on their own.

Nice! Thank you!