The problem you have is not unusual. It seems like you have developed an allergy to fish. Although this does not mean that you are necessarily sensitive to ALL types of fish in most instances this is the case. It would be best therefore to exclude fish and fish products from your diet but incase you find that difficult try by process of elimination to check if there is any particular fish that is causing the problem. This carries its own risks because while you are checking this out certain types of seafood like shell-fish (eg prawns) can cause a severe reaction with swelling of the face, rash and choking so keep an antihistamine like chlorpheniramine maleate handy and a doctor in sight.