bull sharks spawn in fresh water, i have heard that they can live in fresh water around 3 years or so, dont think they could live their whole lives in fresh though. also they would get way too big for almost any home aquarium.
Maybe if u had a specially made BIG lake in a warmish climate it could work. Then put a diving board by it. Or a tiny island in the middle with all your valuables.
Yes - Bull Sharks can live for a couple of years in freshwater - but there's some debate to if they can live their entire lives in Freshwater.
As for what would be required - to keep a bull shark - think at least a good size public aquarium (250,000-300,000 gallons). Or maybe something as large as a good size (1/4 acre+) private pond.