Place the parsley in the stomach cavity of the fish and set it on a large piece of heavy-duty aluminum foil. Roll up the sides of the foil so that you have a very shallow pan around the fish.
Have your barbecue fire ready. I prefer to do this in a Kamado smoker or a covered smoker.
Place the fish in the cooker and close the lid. Watch the temperature carefully and in 25 minutes test the fish. The meat should just begin to flake, but still be moist.