ya, i was at the Shedd Aquarium in Chicago a few years ago...they had a jellyfish tank, and the tour guy was goin on about how they need to have a circular tank (in captivity of couse) because they're very fragile, and if they hit anything...they'er pretty much goners i guess...the tank is circular so that the flow just carries them in circles, instead of blowing them straight at a wall...in the wild they just swarm out in the middle of open water, sometimes the swarms go on for miles and miles of jellyfish...kinda freaky actually...they have stuff like that on discovery channel a lot
and theres freshwater jellies?