Paramecium Dancing

Here's a video I recently took of a little paramecium dancing on the surface of a zebrafish embryo I was examining.  Pretty cool.  Unlike tissue culture, where it is essential to keep a sterile environment, for developing zebrafish embryos it's not a bad idea to have a few (but not too many) of these paramecia around...the embryos can use them for food, setting up a tiny little ecosystem inside your petri dish.