The one thing
Two things matter — (1) the type of fish (oily fish = omega-3s) and (2) mercury (small/oily = low; big predators = high). Everything else is context.
On the package
Tap a claim to see what it does and doesn't tell you.
The honest bottom line
For your health: (1) pick oily fish for omega-3s (salmon, sardines, mackerel, trout); white fish is fine, just leaner. (2) keep mercury low — enjoy the small ones, go easy on big predators.
Wild vs farmed is real but nuanced; 'sustainably sourced' (with a real MSC/ASC logo) is about the ocean; 'fresh' is often just 'previously frozen' — and frozen is great.
Something interesting
A lot of "fresh" fish at the counter was frozen at sea and thawed for display — while the freezer-aisle fish was flash-frozen within hours of the catch. Sometimes the frozen one is the fresher fish.
Look at you, out-nerding your dinner table 🎉
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