In order to get the actual fish on the wall, a reproduction is impossible. Your method of storing the fish was pretty good. You should also make sure the fins aren't bent up when putting it in the freezer. A good method, in the future, would be to wrap the fish in a wet towel and put in a zip lock or whatever. Make sure the fins are down and you'll be fine. As far as taking care of it, dusting is fine.

congrats on the fish.