The US Centers for Disease Control and Prevention (CDC) reported that people that eat large predatory fish may be at risk for a food poisoning called ciguatera poisoning. Some examples of predatory fish are barracuda and grouper. These fish ingest some marine algae which contain a toxin called Gambierdiscus toxicus. Symptoms of ciguatera poisoning are nausea, vomiting, diarrhea, plus numerous neurological symptoms, such as weakness, tooth pain, difficulty walking and changes in temperature sensation.
There is no way to test the fish for these toxins before they are sold. The only way to prevent eating fish contaminated with the toxin is to know which fishing areas may contain the toxins.