Thursday, while we were at War Eagle Caverns, my wife and son were feeding the fish, and she hollered out to me and our cave guide, "Are these Jellyfish?" To which the man replied "No, Jellyfish are only in salt water." I tended to agree with the man, but my wife knows what a jelly fish is, so I left him to go see.
Sure enough, there were these things in the water that looked like Jellyfish. So I did my best to take pictures of them. I didn't expect them to come out, so I tried doing a rough sketch of what they looked like to try to find them online later.
When we got back to camp, I pulled out my phone and sure enough, freshwater jellyfish to exist and she had found some there in Beaver Lake.
I looked up this picture earlier to show you what they looked like with a good picture. This picture came from USGS.
You'll need to click my links to see it better.