ID please
 

I have a piece of Ricordia that is attached to this thing that is very light and seems almost hollow. It has two red holes, one at each end that open (as seen in the picture) and will sometimes be closed up tight. I think it is alive. Sorry for the poor quality picture.
http://www.canreef.com/photopost/dat...a_what-med.jpg

What you describe sounds like a tunicate.

I think you may be right. Here is one of the articles I found.
Thanks.
http://depts.washington.edu/fhlk12/S...n.biology.html