jelly fish????

You can find them at saltwater aquarium fish tank jelly at jellyquarium.com. The main jelly you'll find is going to be a moon jelly or an upsidedown jelly. My LFS will sell these sometimes, mainly the upsidown. They are a little on the difficult to keep and require a lot of maintanence and if you want to propagate or not, you really don't have a say in the matter. They drop efilla into the tank and th create small polyps on the bottom of the tank and if they jelly touches them, because the efilla are very stingy, they will sting the jelly's, like a moon. also, you will need to get a spray bar to keep the jelly from touching the surface of the water as well as the sides, to keep it from damaging itself. Ultimately you will need at least 2 or 3 tanks to keep them healthy because they reproduce so much, you have to empty the entire tank out and move the jelly to another tank and though moon jellys aren't very stingy, if you get something like a seanettle, they could verywell burn you. If you are willing to dedicate daily maintanence, then you will have success, if not, then I don't recommend them for anyone.

Yes they are beautiful, and many are just stunning, they are a lot of work and not for a novice or intermediate aquarist. There are still more and more details in this subject and if you want more info I can point you in that direction, but dedication will keep them alive.