6 Healthy Fish to Eat and 6 to Avoid

Updated November 16, 2018.

You probably already know that you’re supposed to be eating fish twice a week. Fish are a lean, healthy source of protein–and the oily kinds, such as salmon, tuna, and sardines–deliver those heart- and brain-healthy omega-3 fats that you should also be getting in your diet. But then there’s the concern about choosing seafood that’s sustainable. Knowing what seafood is best for your health and the environment isn’t always easy.

Fortunately, Seafood Watch, the program run by the Monterey Bay Aquarium, has combined data from leading health organizations and environmental groups to come up with “Super Green: Best of the Best,” their list of seafood that’s good for you and good for the environment. To make the list, last updated in January 2010, fish must: have low levels of contaminants–below 216 parts per billion [ppb] mercury and 11 ppb PCBs; be high in health-promoting omega-3 fats; and come from a sustainable fishery.

Many other options are on the program’s list of “Best Choices.” The Blue Ocean Institute also has sustainability ratings and detailed information.

According to Seafood Watch, here are six fish that are healthy for you and the planet.

1. Albacore Tuna (troll- or pole-caught, from the US or British Columbia)

Many tuna are high in mercury but albacore tuna–the kind of white tuna that’s commonly canned–gets a Super Green rating as long as (and this is the clincher) it is “troll- or pole-caught” in the US or British Columbia. The reason: Smaller (usually less than 20 pounds), younger fish are typically caught this way (as opposed to the larger fish caught on longlines). These fish have much lower mercury and contaminant ratings and those caught in colder northern waters often have higher omega-3 counts. The challenge: You need to do your homework to know how your fish was caught or look for the Marine Stewardship Council (MSC) blue eco label.

2. Salmon (wild-caught, Alaska)

To give you an idea of how well-managed Alaska’s salmon fishery is, consider this: Biologists are posted at river mouths to count how many wild fish return to spawn. If the numbers begin to dwindle, the fishery is closed before it reaches its limits, as was done recently with some Chinook fisheries. This close monitoring, along with strict quotas and careful management of water quality, means Alaska’s wild-caught salmon are both healthier (they pack 1,210 mg of omega-3s per 3-ounce serving and carry few contaminants) and more sustainable than just about any other salmon fishery.

3. Oysters (farmed)

Farmed oysters are good for you (a 3-ounce serving contains over 300 mg of omega-3s and about a third of the recommended daily values of iron). Better yet, they are actually good for the environment. Oysters feed off the natural nutrients and algae in the water, which improves water quality. They can also act as natural reefs, attracting and providing food for other fish. One health caveat: Raw shellfish, especially those from warm waters, may contain bacteria that can cause illnesses.

4. Sardines, Pacific (wild-caught)

The tiny, inexpensive sardine is making it onto many lists of superfoods and for good reason. It packs more omega-3s (1,950 mg!) per 3-ounce serving than salmon, tuna, or just about any other food; it’s also one of the very, very few foods that’s naturally high in vitamin D. Many fish in the herring family are commonly called sardines. Quick to reproduce, Pacific sardines have rebounded from both overfishing and a natural collapse in the 1940s.

5. Rainbow Trout (farmed)

Though lake trout are high in contaminants, nearly all the trout you will find in the market is farmed rainbow trout. In the US, rainbow trout are farmed primarily in freshwater ponds and “raceways” where they are more protected from contaminants and fed a fish meal diet that has been fine-tuned to conserve resources.

6. Freshwater Coho Salmon (farmed in tank systems, from the US)

Freshwater coho salmon is the first–and only–farmed salmon to get a Super Green rating. All other farmed salmon still falls on Monterey Bay Aquarium’s Seafood Watch “avoid” list for a few reasons. Many farms use crowded pens where salmon are easily infected with parasites, may be treated with antibiotics, and can spread disease to wild fish (one reason Alaska has banned salmon farms). Also, it can take as much as three pounds of wild fish to raise one pound of salmon. Coho, however, are raised in closed freshwater pens and require less feed, so the environmental impacts are reduced. They’re also a healthy source of omega-3s–one 3-ounce serving delivers 1,025 mg.

A number of environmental organizations have advocated taking many fish off the menu. The large fish listed below are just six examples of popular fish that are both depleted and, in many cases, carry higher levels of mercury and PCBs. The Environmental Defense Fund (EDF) has also posted health advisories on some of these fish at edf.org.

1. Bluefin Tuna

In December 2009, the World Wildlife Fund put the bluefin tuna on its “10 for 2010” list of threatened species, alongside the giant panda, tigers, and leatherback turtles. Though environmental groups are advocating for protected status, the bluefin continues to command as much as $177,000 a fish. Bluefin have high levels of mercury and their PCBs are so high that EDF recommends not eating this fish at all.

2. Chilean Sea Bass (aka Patagonian Toothfish)

Slow-growing and prized for its buttery meat, Chilean sea bass has been fished to near depletion in its native cold Antarctic waters. The methods used to catch them–trawlers and longlines–have also damaged the ocean floor and hooked albatross and other seabirds. At present, there is one well-managed fishery that is MSC-certified. EDF has issued a consumption advisory for Chilean sea bass due to high mercury levels: Adults should eat no more than two meals per month and children 12 and younger should eat it no more than once a month.

3. Grouper

High mercury levels in these giant fish have caused EDF to issue a consumption advisory. Groupers can live to be 40 but only reproduce over a short amount of time, making them vulnerable to overfishing.

4. Monkfish

This strange fish resembles a catfish in that it has whiskers and is a bottom-dweller, but its light, fresh taste made it a staple for gourmets. The fish is recovering some after being depleted, but the trawlers that drag for it also threaten the habitat where it lives.

5. Orange Roughy

Like grouper, this fish lives a long life but is slow to reproduce, making it vulnerable to overfishing. As Seafood Watch puts it: “Orange roughy lives 100 years or more–so the fillet in your freezer might be from a fish older than your grandmother!” This also means it has high levels of mercury, causing EDF to issue a health advisory.

6. Salmon (farmed)

Most farmed salmon (and all salmon labeled “Atlantic salmon” is farmed) are raised in tightly packed, open-net pens often rife with parasites and diseases that threaten the wild salmon trying to swim by to their ancestral spawning waters. Farmed salmon are fed fish meal, given antibiotics to combat diseases and have levels of PCBs high enough to rate a health advisory from EDF. Recently, however, freshwater-farmed coho salmon have earned a Best Choice status from Seafood Watch. Consumer pressure may encourage more farms to adopt better practices.