Are these sponges?

[mdbronco]

Anything in particular I should be aware of with these? Started popping up underneath the rock a few weeks ago and keep spreading and growing.

 

[Sambird2942]

They look to me like pineapple sponges

 

[Paleozoic_reefer]

Definitely sponges...had the same type a few years back but they died out and only have a few in the nooks and crannies in my system...

 

[KJ]

pineapple sponges

Agree and Welcome to R2R!!!

 

[mdbronco]

thank-you!

 

[Sambird2942]

Agree and Welcome to R2R!!!

Thank you

 

[lilgrounchuck]

Yep. They’ll likely come and go depending on how much you feed. I always see them on the back of my pump, but when I start feeding heavier I’ll see more of them pop up on the rock work for a while.