The harmful substances that cause ciguatera, scombroid, and shellfish poisoning are stable, so of cooking will protect you from becoming poisoned if you eat fish that is contaminated.

Ciguatera poisoning normally occurs in larger fish. And it occurs in fish from warm tropical waters.
The harmful substances that cause Ciguatera, Scombroid, and shellfish poisoning are heat stable, so no amount of cooking will protect you from becoming poisoned if you eat fish that is contaminated