Do you think that this fish could kill you? Maybe not, but this fish could damage your nervous system, cause behavioral disorders, give you headaches, and can lead to death, because, it has methyl-mercury in it.
Mercury comes from things like coal power-plants or factories.
The most common way to contract mercury is by eating fish.
When wast from coal burning or mining iron can cause mercury to get into water where it contaminates fish.
To stop people from getting methyl-mercury, coal power plants and factories need to have precautions that prevent mercury from getting into the environment.
The infected fish get taken to be sold and eaten spreading the mercury.
Mercury can also spread to other animals that consume the fish which can damage the ecosystem.
Mercury is a teratogen, meaning it can cause birth defects by damaging the nervous system in new born if their mothers consume it. There is evidence to suggest that it may be carcinogen, so it may cause cancer.
People can also be careful with what and how many fish they eat to avoid contracting methyl-mercury.