The most dangerous fish to eat tend to contain toxins from their diet. Pufferfish are thought to be the most poisonous. They harbour a potent neurotoxin called tetrodotoxin, which comes from bacteria in their diet.
When humans consume the toxin, it blocks nerve signals, which can lead to paralysis, respiratory failure and even death.
Symptoms generally appear between 20 minutes and 3 hours after ingesting the toxin and there’s no known antidote.
In Japan, related toxic blowfish are a delicacy called fugu, requiring specially trained and licensed chefs to prepare them for consumption.
Eating a kind of sea bream called salema porgy (Sarpa salpa) can cause strong, LSD-like auditory and visual hallucinations in humans.
This hallucinogenic phenomenon is called ichthyoallyeinotoxism and only happens at certain times of year, leading to a theory that the toxins come from algae or phytoplankton.
The fish live in the East Atlantic and the Mediterranean and are colloquially known as ‘dreamfish’ for their mind-bending toxicity.
Fish living in coral reefs can contain a neurotoxin known as ciguatoxin, which comes from ocean algae called dinoflagellates.
Tiny fish survive on the dinoflagellates and, in turn, are eaten by larger fish. Most of the highest ciguatoxin carriers are predatory reef fish like barracudas and moray eels, but common fish such as red snapper and sea bass can be contaminated.
The highest toxin concentrations are in a fish’s head, liver and intestines.
In humans, symptoms can appear just 30 minutes after eating contaminated fish, which can affect the digestive and nervous systems.
Climate change is predicted to exacerbate the problem by driving up levels of the dinoflagellates, which thrive in dead or dying coral reefs.
Mercury is another neurotoxin that builds up along the food chain in oily fish. It’s worth restricting consumption of fish particularly high in mercury, including king mackerel, swordfish and shark.
This article is an answer to the question (asked by Henry Buckley, via email) 'What is the most dangerous fish to eat?'
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