There are incredible amounts of mercury in fish .
From a commenter named Ariel:
Years ago a lady who I know told me about her friend who ate a “Whaler” from Burger King. Her friend immediately thereafter became permanently and severly neurodamaged due to the mercury.
A White dude we knew was livin in Shanghai, and he adopted a daughter some years back. Who’d ‘ve thunk it? She went around eatin fish, though the stepdad told her not to. And a couple years back, she went out on her own to eat fish in a “lestolung” and indeed went nuts after eatin it. Knowin bout the water quality problems in China, you’d have to be at least somewhat insane to even try it. She became so disoriented after eating the fish that she called him and admitted she had no idea where she was. The problem was so bad she couldn’t leave the house, and for about three months her eyes malfunctioned to the point where she couldn’t see anything but vague light indications. Even after significant recovery, she is unable to function in society and is essentially hospitalized at home on a permanent basis.
There is also a poster on Youtube who does tutorials on chelating enemas. He explains that he was hospitalized in France for schizophrenia for four years when a curious nurse asked him if he ate fish before he went crazy. He said yes, and the nurse explained that chelation (removal of heavy metals) might help his condition. He tried it and is now a normal person teaching chelation on Youtube. Nevertheless he doesn’t recommend eating fish as “brain food.”
Also of interest:
- Government studies show that eating just one can of tuna per week can increase a person’s mercury level to 30 percent above levels considered safe.
- Mercury is known to cause severe health problems for humans, including brain damage, memory loss, tremors, and damage to a developing fetus. 
So remember next time you get to the dinner table. Don’t eat that brain-damage food – fish!
(Shoot. I should show this post to my mom.)