Freshwater Jellyfish

I hate to bring this up this way but here goes. About 8 years ago, my dad and i were fishing in Mauch Chunk, a lake near Jim Thorpe, PA. We had just launched our boat, and had trolled about 100 yards from the ramp. I looked down, and we were surrounded by a cloud of jellyfish. There had to be thousands of these things. As i recall, they were about the size of a half dollar, an about an inch or two tall. just wondering if anyone knew anything about these creatures, what they are, and whether or not i could keep them in a tank if i manage to run into them again.

I'm sure someone will post all the specifics on them, but there is alot of info on the web. First time I ever saw them I was a few yedars ago in the summer while out fishing and figured I just had way too much to drink. There are only a handful of lakes in my area that are still clean enough to have theses animals. Wish I had my log book right now, I printed out a bunch of info and pictures because my dumb friends thought I was just fried again. Sure you can google anything you what to know. I never tried to collect them, I assumed they need them same type of tank there saltwater cousins do where its always rotating and they never make contact with the sides. Wish I could help more.

At a watershed meeting last year I found out that Rose Valley Lake is the only place in Lycoming County to have these things. I have actually never seen them though. I'd imagine they'd need excellent water quality though.

The place to go for fw Jellies is here: http://www.jellyfish.iup.edu/