Fish

Any of many cold-blooded vertebrate animals living in fresh and salt waters worldwide, from the primitive jawless lamprey through cartilaginous sharks, skates and rays to the abundant bony fishes that include most food fish. Fish supply high-quality protein and omega-3 fatty acids; safety concerns include parasites, histamine, heavy metals and ciguatera. Global consumption exceeds 20 kg per person annually, with aquaculture now supplying over half. Nutritional guidelines promote oily fish for EPA and DHA, while advisories limit predatory species — shark, swordfish — for pregnant women due to methylmercury. Parasite destruction by freezing and histamine control by chilling are the core safety measures.