It’s like a step above reef keeping, in some ways. They require special tanks without corners to keep them circulating away from surfaces, with a fairly calm, laminar boundary. They’ll typically rotate the flow around the tank and jellyfish swim against it, keeping them “suspended”. Beyond that and normal saltwater chemistry, there is the food. They require food pretty much every day. I would grow, enrich, and freeze of brine shrimp that I would partition out. Water changes would happen every week or two, I didn’t want my nitrates above 15 ppm or so. Vacations were hard as they required a lot of attention. Nettles are way more voratious predators, so I’d sometimes feed them twice a day with protein-heavy options. Only got stung once by these guys, and it was because some nematocysts must have gotten on a sponge when cleaning and I wrung it out. Wasn’t too bad.