In Oklahoma, we have huge populations of Spoonbills / Paddle fish. Fishing is heavily regulated. The Spoonbills congregate below huge dams, facing the strong current & filter feed. Methods of catching them include "Snagging" w/ enormous treble hook & "Bow hunting". I know of no local public aquarium that exhibit Spoonbill. I imagine feeding and environmental requirements are unattainable. Its important to note that these, several public aquariums, display native monsters such as Alligator Gar, Flat Head & Blue Cats even Stripers / Striped Bass. I don't fish for Spoonbill, but I did once help a Bow hunter pull in a baby 20 lb. Spoonbill.
Quite an impressive fish, but the thought never occured to me to keep one in captivity. Even if you could legally obtain a Paddle fish, IMO there is really no way to keep it.