I agree with everyone else! Why would you want to take the guy out of your 800 gallon tank? Make the 800 gallon into a cool predator tank and move your other fish into the 200 gallon.
Not to be mean sounding, but didn't you know before getting the shark they will eat your other fish? They are predators and anything in that tank that is not as big as them is pray.
If you really like your Shark and like him greeting you every day, I would keep him in the 800 gallon tank and have an awesome predator tank.
I would go with a few Sting Rays for tank mates and another Cat Shark or Bamboo Shark. With an 800 gallon you can put so much in that would be fine with your Cat Shark that you wouldn't miss any of your small fish in there.
Maybe some Big Groupers like the Spotted Coral Grouper, a BIG Lion Fish, or even a nice sized Eel would go well.
I just think taking him out of the 800 gallon home and into a smaller 200 gallon would be cruel to him. It's one thing if he was put into the 200 gallon from the start, but to go from a 800 gallon to a 200 gallon would suck for him.