Mercury in fish, what are the effects on your body?

Neurological. Minamata disease is the name for the effects of mercury poisoning on the body which are chiefly neurological. These include ataxia, numbness in hands and feet, muscle weakness, narrowing of the field of vision and hearing and speech damage. In extreme cases, insanity, paralysis, coma, and death occur within weeks of the onset of symptoms. Fetuses in the womb can also be affected.