Cocoons

I have these white cocoons poping up all over my live rock it's getting to a point where there covering everything they look like little oval cotton cocoons with a small opening at the top. anybody know what they might be and how do I get rid of them or control there numbers.

 

little sponges.

 

To be a little more specific, now that I have made it through my first pot of coffee, a calcareous sponge.

 

aren't those made from calcium carbonate spicules? these things you can squeeze with your finger and they feel squishy like wet cotton they fall apart real easy. I'll try to get a pick.

 

It's a sponge. I got the name from Shimek. Looks like a pineapple. They get everywhere, in the equipment rocks...you name it. I hear tales that their population can depend on the nutrients found in the water.

 

here is a pic closest I could get.

 

Sponges.

 

About 5mm in lengh? I have 100s of them in my Nano, they usualy apear in mature systems.

 

yeh about that length. +1 to hundreds of them.
They are all over top of my heater to the sides of the glass.:-/
just wanted to make sure they won't hurt the coral.
I'm assuming there a filter feeder because of the fine fibers near the opening.