I see freshwater jellyfish every summer in massive shoals, sometimes comprising of several thousand individuals, in Power's Lake CT. The first time I saw them I was amazed as I'd never seen anything like them before, at least not in fresh water. They are quite small, the largest being about 1.5x the diameter of a one cent coin. These creatures apparently aren't really true jellyfish in the scientific sense but they look and swim like the 'real thing'. Several marine 'jellyfish' aren't 'true' jellyfish either (some are related to these) so I guess there's nothing too wrong in their common name usage. Their scientific name is Craspedacusta sowerbii and they are only found in relatively still and pollution free water. They do have stinging cells on their tentacles but they appear to be incapable of stinging people, probably because their weapons are only effective on very small creatures with thin skins. I have swum through large shoals of these creatures and felt nothing but fascination and amazement. This year I took a disposable tissue culture flask from the lab with me so I could attempt to get some half-way decent pictures of some temporarily captive specimens, here are some of the results. I shot the photos using my Nikon Coolpix 995 through the flask. I tried a few different backgrounds; when I used the sky as the back drop the presence of the odd cloud made the jellyfish look somewhat like UFOs.