Biotoxicology is the Knowledge of plant and animal toxins. The Poison is a generic word and usually refers to the poisons that are edible. From this point of view it can be said that all venoms are poisons but every poison is venom. The Poisonous fish are divided into two categories of poisonous fish (cryptotoxic) and venomous fish (phanerotoxic). The toxic fish are divided into different groups based on the toxin storage location and its chemical nature. The venomous fish are able to adapt to the condition that it can conceal itself through the piercing or scarring organs, and the venom is focused on specific numbers. Of the 900 species of fish in the Persian Gulf, about 18% are 90 toxic species, about half of which are poisonous. Therefore, knowledge of different families of these fishes and their physiological effects on human body is important for medical and medical practitioners, especially in coastal provinces. The most important poisonous fish orders are Tetraodontiformes, Perciformes, Clupeiformes, and the most venomous species include perciformes, rajiformes silurifomes, Batrachoidiformes and Scorpaeniformes.Chemical toxins and their effects on the nature of fish are often considered to be neurotoxins and it must be stated that despite the risk to humans, various medicines can be extracted from these toxins.