A white minefield/puff ball

[Safedad]

I added a piece of rock a few weeks back. There is something white growing on it. One of my peppermints ate about half of it the first day. It has grown back and now has spikes with small puff balls on the end. Rminds me of pictures of an underwater explosive in a minefield. It is about 1/4" to 3/8" around so I can't get a picture with my camera. It is white, round, spikey with narrow threads stiking out. The threads have small versions of the center plant. Anyone know what it is. It is neat looking but will the little puffs break of and spread with no know cure??
Thanks,
Bob in Cary NC

 

[fishcrazy]

Bob,

This is nothing to worry about. It sounds like a Scypha ciliata sponge. They are often called Q-Tip sponges or Pineapple sponges based on their appearance. They are harmless and actually help you avoid diatom blooms because they utilize silicates as well as Calcium. Their populations will wax and wane so don't worry if they go away and come back later.

 

[jkhalliday76]

Safedad,
I know this picture isn't great, but if what you're talking about looks anything like this...it's indeed a q-tip sponge.

 

[Safedad]

No, don't think so. I took your suggestion and did a search. The closest thing I came to was tetilla zetlandica. It is more like a white puff ball with little puff balls hanging onto it. Fish, snails, crabs, shrimp, and now sponges! What an interesting hobby.
Thanks,
Bob