Scombroid food poisoning can cause hives. This kind of food poisoning comes from fish that have spoiled. Hives are one of the first symptoms that could appear, in addition to all of the usual food poisoning symptoms - such as vomiting, diarrhea, and cramping in the abdominal area. Scombroid, however, tends to appear more like an allergic reaction to fish. Take heart, lovers of fish. It doesn’t mean you’re allergic to fish. It just means you got a bad fish.
If you’re worried about your health after eating a fish, a trip to the doctor wouldn’t hurt anything. If it’s nothing more than mild food poisoning, the doctor can give you a few tips on how to rough it out. However, if you’re in serious danger of having other symptoms or have had more serious symptoms, going to the doctor could save your life.