https://safecatch.com/ This is the kind of Tuna we eat. Its not cheap but they test it for Chemicals before they try to sell it.
You would think that most of the fish in the Pacific ocean would be full of radioactive isotopes with all of the bombs and the Fukushima disaster that is still going on.
We will all die eventually from something different. Tainted fish is still probably better than eating too much red meat. I don't worry about it much because I don't eat it every day.
It's not radiation to worry about. The levels from Fukushima are miniscule in the Pacific Ocean and in fish.
It is Mercury (very toxic to humans), that should worry most people.