Ciguatera, or fish poisoning, is an illness caused by eating fish containing certain toxins. These toxins come from a type of algae, and get into the fish either through it eating the algae, or eating fish which have eaten the algae.
It can cause symptoms like nausea, vomiting, and tingling fingers or toes. It can also make cold things feel hot and hot things feel cold. It has no cure. Symptoms usually go away in days or weeks but can last for longer.