Subject: Are there any living organisms that do not breathe?

I realize the answer to this question depends upon your definition of the 
word "breathe."  While some might say that plants do not breathe, they do 
take CO2 from the air and use it in photosynthesis.  For the purposes of 
this question, I would consider that breathing, but correct me if I'm wrong 
about that.  Similarly, I would consider fish taking oxygen out of water 
breathing too.

Thanks

Re: Are there any living organisms that do not breathe?