This is how I was imagining Fish's enclosure

It's pretty large, the area at the bottom is a sort of glass walled viewing area (mostly to protect people from having their ankles bit)

Sandy area for Fish to relax on the 'beach', and a large basking rock with optional heat lamp. All you need to take care of your pet shark thing!

His chain is attached to the bottom of the pool, and there's a gear that can adjust the length for personnel and cleaning staff safety. They definitely deserve hazard pay