Blowing bubbles in water?

Took Nergal out and gave him a quick bath (he had blood on him from feeding day). After a minute or so he dunked part of his head under water and started blowing little bubbles.
He didn't wheeze or anything when he came up for air, and didn't blow bubbles again after that. He's never done it before.
Is that normal?? I did find a little mouse hair on his lip, but not near his nose.
What the heck was he doing? :P

They do it from time to time. I'll hear them doing it sometimes when give fresh water on cleaning day. Ever blown bubbles with a straw into your drink? You can't tell me its not entertaining ;)

My Bloods do it alot too

Like Luke said, noticeably on days when fresh water is given to them

nothing to worry about. most of the time i put mine in water they dunk their heads and do this. i think they are just looking for a way out as none of mine ever seem to enjoy the water.