Identification organism on Live Rock

[AngryCuttlefish]

Hi guys
I'm not able to recognize this organism

 

[ChiCity]

pineapple sponges,
they proliferate in a new system…
then fade away.

nothing to worry about

 

[jda]

Yup. They are good, effective filter feeders. If you have really good parameters and stuff, they can live in the shadows behind the rocks or in the sump or other dark places. They die off in some tanks if no3 gets too high.

 

[AngryCuttlefish]

I was thinking about that but I wasn't sure! Thanks