Seafood Nutrition -
Health Benefits of Eating Fish & Seafood

Best Fish for Omega 3:

Wild Salmon - Fresh, frozen, or canned are all OK. Wild salmon will cost you
a lot more than the farmed variety, but salmon farming practices produce
waste and can spread parasites and disease to wild fish, among other
problems, according to Seafood Watch

Arctic Char - Farming practices for arctic char aren't linked to pollution
or contamination, so it's fine to opt for farmed over wild-caught (which
isn't as easy to get anyway). At a sushi bar, you may see it called iwana.

Atlantic Mackerel - Mackerel populations in general are hardy, so
wild-caught is A-OK. But because the EDF recommends you limit consumption of the Spanish Mackerel and king varieties of mackerel because of the potential for mercury contamination, stick to Atlantic mackerel as a staple.

Sardines - These tiny fish generally come from the Pacific, where the
population has resurged. Because they're small, they don't come with the
mercury worries of fish higher up the food chain.

Sable Fish or Black Cod - Seafood Watch recommends you stick to fish caught
off Alaska and British Columbia, where fishing practices have reduced the
likelihood of the accidental catch of other species.

Anchovies - Exact species isn't important; they're all OK, says the EDF.
These fish reproduce quickly, so they aren't threatened, and they're small
enough so that contamination is not an issue.

Oysters - Farming operations produce the vast majority of oysters. They are
generally well managed and have a low impact on the environment, so farmed
oysters are a great choice. At the sushi bar, you may see oysters called
kaki.

Rainbow Trout - Because lake trout in the Great Lakes have been overfished,
Seafood Watch recommends farmed rainbow trout, or golden, trout as the best
choice. Because of moderate PCB contamination, the EDF recommends kids limit consumption to two to three meals a month, depending on their age.

Albacore Tuna - Albacore Tuna. Kids up to age 6 should limit consumption to three meals a month because of moderate mercury contamination, the EDF says.

Farmed Mussels - Farmed mussels are raised in an environmentally responsible manner-in fact, the operations may actually improve the surrounding marine environment. You may see them called murugai at a sushi bar

Pacific Halibut - There are lots of different varieties of halibut, but
Seafood Watch recommends the wild-caught Pacific (also called Alaskan)
variety. Atlantic stocks have declined and are under pressure, and
California halibut is caught using less preferable fishing methods. Kids
should limit consumption to a few meals a month because of potential for
mercury contamination.

Above is from Monterey Bay Seafood Watch Program