Some Asian farmed fish are packed with various pollutants that come along with mass fish farming, but I think that's generally for exporting to western countries. If you're in Asia, Japan in particular has extremely high standards for their fish, I wouldn't worry too much. Many of my relatives still live is east Asia, living on a diet of primarily rice and fish, and living well into their 90s. Hope that eases your mind.
F 28/5'4/100 lbs
"I'm not a psychopath, I'm a high-functioning sociopath; do your research."