Cassiopea Xamachana..[AKA] The mangrove upside down jellyfish,Is pretty hardy as far as maintainance and up keep go,I use to keep a few of them with a fine substrate,and soft current,in a 20 high,,You would want to keep by themselves,other tank mates will eat the food before they can get it,but the cool thing about them is they are photosynthetic,so have good lighting on your tank,they will move around the tank so,have the strainers of your powerfilter covered with a large fine foam filter,so if the run into it they can basically jump off of it,You can feed them brine shrimp,If you use other shrimp use small pieces without the shell,and a small piece of fish they will consume....Hope this helped...They don`t live long,the ones you get in the aquarium trade are older....They are very hypnotic to watch ..
You need spherical or circular tanks so that the jellies(which cannot move on their own) dont get stuck in the corners and then get beaten up by the flow. When you do this, you shouldnt need any powerheads as a low flow pump behind the corner or under the tank keeps it moving very well.
Theyre not terribly difficult to maintain, as they just need a water change 1x a month and a healthy diet of live food. But like any animal that we take in, there has to be a solid routine established.
The easiest to care for in the aquarium trade are moon jellyfish and stay pretty small.
A pretty cool fact is that most of the time, the jellyfish will turn or shade into the color of whatever you feed them. That mixed with some pretty awesome LED's make for a beautiful display.