There are a couple of kinds of food poisoning one can get from fish. They are scombroid and ciguatera food poisonings. They are two different kinds of food poisoning, and gotten in two different methods that ultimately end up with you eating the contaminated fish. The first method is simply that you’re eating a fish that has spoiled. That’s the scombroid poisoning. Ciguatera poisoning is caused when you eat a fish that has already been contaminated with ciguatera.
The catch here is that you’ll never be able to smell either of the poisonings. Furthermore, cooking (IE heat) and storing (freezing or refrigerating) have no effect on the bacteria that cause the food poisoning. The best way to avoid these is simply to toss fish you think has been contaminated.