ID but no pics
 

I have these while looking things growing on my rocks. I can not get a clear picture of the unfortunately. They are white bulb like in shape with a fine hair like top.. (I noe even sure how to describe these things) they are about 2 mm or so in size.


Any ideas?

I have them too, I always just dismissed them as a type of sponge or something....honestly though, I have no idea. Sorry.

I have them as well. I am in the same boat no Idea

I've always figured they are some type of tunicate. I used to have plague proportions in my sump but the population has since stabilized.

Tunicates are similar in shape, but have 2 vents on them, for processing water through.
What you are probably describing is a sponge choanocyte.
Here's a link to it, about halfway down this page:

http://www.animalnetwork.com/fish2/a...wb/default.asp

Mitch