I’d be wary of eating salmon regardless of the fact that it’s typically considered a low-mercury fish. I developed a mercury toxicity after eating primarily smoked salmon for my fish consumption. I did eat some tuna as well, but not nearly as much. I believe the salmon I ate was farmed since it didn’t advertise being wild-caught on the box, which they almost certainly would do if it was. The salmon I usually bought was from Costco if anyone is curious: http://tastyislandhawaii.com/images14/gravlax/costco_norwegian_smoked_salmon.jpg
My recommendation would be if you already have yeast overgrowth and serious chronic health issues, just avoid fish altogether. Some people on this board will probably disagree with me, but that would be my advice. Trust me when I say that you definitely don’t want any more mercury in your system. I know fish has health benefits in terms of the EFAs provided, but there are safer ways to get them.
All of this is not to mention the Fukishima radiation in the Pacific: http://www.naturalnews.com/044317_fukushima_radiation_west_coast.html
Just my 2 cents.