Need ID help for donuts in my tank

[curiouser]

These are on a rock that I moved up top from the gravel behind my reef yesterday. Not sure how long the rock was there. Probably at least months. The donuts were visible as soon as the rock was placed up top. Reef was started about 4 yrs ago with dry rock. I assume this was a hitchhiker from when I added a coral attached to a rock. Last coral addition was a few mos ago.
In the pics you can see some white donuts which look like little volcanoes on side view. Diameter about half an inch.
Would appreciate any help with ID.

 

[AcroNem]

I don't have a Genus for these, but they are sponges, they're harmless and feed on phytoplankton, dissolved organic matter, bacteria etc.

 

[Sailingeric]

Pineapple sponge, they will go away. I got them a couple months ago and within a couple weeks they were gone. Harmless.

 

[AcroNem]

I respectfully disagree on them being pineapple sponges, but populations of sponges in home aquaria will fluctuate based on nutrient levels and the amounts of particulates in the system.

 

[ZoWhat]

Pour yourself a cup of coffee and enjoy the view of your donuts

 

[Michael Naegeli]

Mmmm.... Donuts

 

[Sailingeric]

I respectfully disagree on them being pineapple sponges, but populations of sponges in home aquaria will fluctuate based on nutrient levels and the amounts of particulates in the system.

You might be right. I had something similar and that is what I got when I posted a "what are they" question. ;)

 

[curiouser]

Thanks for all the responses.
Eases my mind.