How can i be sure that my new symptoms are causes by fish i had recently ate butter fish and trout my tongue is swollen and i itch?

Timing: If you have an allergic reaction to the fish you ate, it will happen quickly, after consumption, usually within an hour. If you consumed different fish, it could be one or the other. Also, it could be from contaminants on the fish and not the fish itself.

Allergic response: Allergic response can cause airway closure, so until diagnosed EAT NO SEAFOOD. Make an appointment with a specialist Allergist for examination and testing.