Is Fizz Jungle still viable?

No, Fizz "Anything" isn't particularly viable, but building anything but defensive-AP would kill you.

Can work even with the old build but not the strongest. He is much better now as an ap mid laner or if you fan of tanky bruiser fizz play him on top with + then go full tank or a if you are ahaed. But ap is the best for him and jung is the worst atm (after bot ofc).