Ciguatoxin

Ciguatoxins are a class of toxic polycyclic polyethers found in fish that cause ciguatera.

Some ciguatoxins lower the threshold for opening excitatory voltage-gated sodium channels in the nervous system.

Opening a sodium channel causes depolarization, which could sequentially cause paralysis, heart arrhythmia, and changing the senses of heat and cold.

The major symptoms will develop within 1–3 hours of toxin ingestion: vomiting, diarrhea, numbness of extremities, mouth and lips, reversal of hot and cold sensation, muscle and joint aches.

The toxin usually accumulates in the skin, head, viscera, and roe of big reef fish like grouper, wrasse, triggerfish, lionfish, and amberjack.