Seafood Watch, a program run by the Monterey Bay Aquarium, has combed through data from health organizations and environmental groups to come up with easy-to-understand recommendations for seafood harvested all over the globe. Look for their “Best Choices” labeled in green on the site. Another easy way to identify good picks is to look for the blue Marine Stewardship Council label when you’re shopping—it identifies certified sustainable seafood. The Monterey Bay Aquarium Seafood Watch program offers a list of sustainability ratings and detailed information on specific fish while the Environmental Defense Fund (EDF) provides up-to-date mercury notices. And what if you eat fish caught by family or friends or that you’ve caught yourself? Look for fish advisories put out by local health or fish and game departments. For the healthiest fish, look no further than this list. We took safety (in the form of mercury) and the environment into consideration, too, when building this list of the best fish to eat (and some to potentially avoid).

Best Fish to Eat

Go on, use this cheat sheet to start adding more healthy seafood to your diet.

1. Oysters

There are multiple health benefits of eating oysters: one serving delivers more than 1,000 milligrams of good-for-you omega-3s, is chock full of vitamin B12 (you get well over your daily needs), and nearly all of your daily iron and zinc doses. Plus, 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 important health note: Be cautious when eating raw oysters, especially those from warmer waters, as they may contain bacteria that can cause serious illnesses.

2. Sablefish

Also called Black Cod (though it’s not actually a type of cod), this oily fish is a great way to get omega-3s into your diet. A single serving of smoked sablefish delivers at least 1,000 milligrams, plus it’s a good source of most of the B vitamins, magnesium, phosphorus, and potassium. The EDF considers sablefish to be both eco-friendly and a healthy best choice. And Seafood Watch has rated it a “Best Choice” for the environment when fished out of Alaska.

3. Salmon

Low in mercury and high in omega-3s (you’ll get at least, if not more than, 1,000 milligrams in a serving), salmon is a healthy fish choice that most of us are familiar with and enjoy cooking with in salmon recipes. Plus, it’s readily available at grocery stores, and restaurants, making it that much easier to incorporate into your diet. When considering sustainability, look for West Coast wild (especially Alaska where most of their natural habitat remains untouched), Atlantic farmed, or New Zealand farmed, per Seafood Watch.

4. Shrimp

Shrimp has long been Americans’ favorite seafood, and for good reason—it’s easy to cook, is versatile, mild in flavor, and has good texture. Plus, it’s healthy. A 3-ounce serving has about 18 grams protein (that’s more than a third of your daily needs), is low in fat, and chock full of selenium. Yes, shrimp does deliver cholesterol, but science suggests that dietary cholesterol doesn’t have much of an impact on heart conditions. For the most eco-friendly shrimp choice, purchase Northern Shrimp from the U.S. and Canada, says EDF.

5. Trout

Most of the trout you will find at your grocery store or fish market is farmed rainbow trout, and raised in the U.S. where the farming operations are held to strict environmental standards. What’s more, rainbow trout are a great way to add more omega-3s into your diet (a single serving delivers at least 1,000 milligrams), plus they’re low in mercury.

6. Tuna

Stick to albacore and skipjack (caught via trolls, pole, and lines) as they’re all “Best Choices” for the environment according to Monterey Bay Aquarium. Usually albacore tuna will be higher in calories and total fat, while skipjack tuna is ever-so-slightly lower in calories and has less fat. Skipjack is smaller in size and thus lower in mercury, particularly when compared to canned albacore. The Environmental Defense Fund Seafood Selector says that adults can safely eat canned “white” or “albacore” tuna about once a week, while kids 5 years and younger can safely eat it twice a month and kids between 6 and 12 years can have it three times a month.

Fish to Avoid

Factoring in safety and sustainability here are fish to avoid adding to your meal plan.

1. Atlantic Halibut

Although these flatfish are high in protein and contain other nutrients, they have moderately-high levels of mercury. Plus, both Seafood Watch and EDF suggest avoiding Atlantic halibut as the population is overfished.

2. Bluefin Tuna

Bluefin tuna have high levels of mercury and PCBs—in part because they grow slower and take longer to reproduce—so they should be avoided. In fact, adults are only advised to eat it once a month and kids less than once a month. Another reason to avoid bluefin tuna: they’re extremely overfished.

3. Orange Roughy

High in mercury (it has a long life so it accumulates high levels of mercury) and rated very poorly for its sustainability, orange roughy is a fish to skip, says EDF and Seafood Watch.

4. Swordfish

Also high in mercury, it’s recommended that women of child-bearing age and children steer clear of swordfish. From a sustainability standpoint, U.S.-caught swordfish are OK, but any imported swordfish should be avoided as there is little to no management of the international swordfish fisheries.