The healthiest fish to eat is Wild Caught Alaskan Salmon.
Other healthiest fish to eat include.
Sardines, Pacific (wild-caught)
Rainbow Trout (and some types of Lake)
Herring.
Bluefin Tuna.
Orange Roughy.
Salmon (Atlantic, farmed in pens)
Mahi-Mahi (Costa Rica, Guatemala & Peru)
The most unhealthy fish to eat is the Bluefin Tuna.
The Bluefin Tuna is healthy in moderation but it is high in mercury which makes it unhealthy when eaten in excess.
This, coupled with their exorbitant value in the sushi market, has led to severely depleted populations.
Bigeye and yellowfin, also known as ahi, are common in sushi. Both types, along with bluefin, are high in mercury and should be eaten infrequently, if at all.
Other fish that are considered the most unhealthy to eat include the King Mackerel, Shark, Swordfish and Tilefish.
All fish advisories due to increased mercury levels should be taken seriously.
This is especially important for vulnerable populations such as young children, pregnant or breastfeeding women, and older adults.
Other fish that are not considered very health include.
Chilean Sea Bass (aka Patagonian Toothfish)
Grouper.
Monkfish.
Orange Roughy.
Salmon (farmed)