I would highly recommend contacting Disney directly in this case. Explain to them that you eat saltwater fish at home, etc with no problems. They handle all sorts of allergy concerns on a regular basis and will be able to give you the best current information. Just emphasis that he can eat fish, just not fresh water. I do believe that they have separate fryers for allergies. I have to avoid milk and am pretty sure that my chicken has been fixed in a separate fryer.