Dave Asprey says:
Unfortunately, because of the Norwegian-led fish-farming industry and modern pollution, its no longer safe to assume you’re eating a nutritious, disease and poison-free fish… unless you know exactly where it came from.
Long story short: Avoid farmed fish the same way you avoid industrial red meat, insist on wild-caught sockeye salmon, and boycott Norwegian fish products because their global fish farms have killed 90% of local healthy salmon populations, including the ones 15 minutes from my house. Bastards!
How Norway Is Killing Your Sushi