

Fish are carnivorous, and mercury is bioaccumulative. So, larger fish tend to have higher concentrations than smaller fish, but pretty much all fish have some level of mercury. There is no “safe” concentration.
But the real problem with your scenario is that I’d prefer hunger pangs over fish, grilled or otherwise.
Freshwater fish can still have mercury. Even farmed fish can have mercury contamination, if their feed is sourced from the wild.
Nah, I’m perfectly happy with my hot dogs. You’re the one eating broken thermometers and fluorescent lights.