A common recommendation among healthcare professionals (and mainstream health media) is to eat more fish. But with the sheer amount of seafood options available, making a purchasing decision can be tricky. Even the keenest of health foodies struggle to determine the difference between fish varieties and brands in terms of healthfulness and contaminant levels.

We’ve interviewed a registered dietitian to help you understand which types of fish offer the best nutrition while also containing fewer impurities – and have a lower environmental impact. Read on to learn about some of the healthiest fish to eat.

What Makes Fish More or Less Healthy?

When it comes to fish, not all varieties are created equal in terms of nutritional content and overall health impacts. 

Most fish contain meaningful amounts of protein, B vitamins, and a range of minerals including iron, selenium, zinc, and even calcium in some instances. “Protein is essential for muscle repair, immune support, and keeping you full and energized,” says Kristen Carli, MS, RD. Meanwhile, the other nutrients often found in fish support metabolic, immune, heart, and bone health.

Some of the healthiest fish varieties, however, will also contain omega-3 fatty acids and vitamin D. “Omega 3s are healthy fats that help keep your heart, brain, joints, eyes, and skin in top shape, while also supporting mental health and reducing inflammation in the body, whereas vitamin D keeps your bones strong, boosts your immune system, and can positively impact your mood,” Carli explains.

That said, there are also a range of contaminants commonly found in fish that we want to be wary of—namely mercury, microplastics, and polychlorinated biphenyls (PCBs). “Mercury is a toxic substance, and high levels of intake can affect the nervous system, especially in children and pregnant women,” says Carli. Meanwhile, with the pervasive nature of plastic and chemical pollution worldwide, microplastics and chemical pollutants are more prevalent in seafood sources than ever before.

Microplastics can contain a mix of over 16,000 chemicals, with at least a quarter of those so far known to be toxic to human health. “Meanwhile, PCBs are industrial pollutants that build up in some fish and can harm your immune system, hormones, and fertility,” Carli adds. Conducting research on specific brands of fish or checking sustainable seafood databases like Seafood Watch are great ways to mitigate exposure to these impurities. 

“Wild-caught fish also generally have less exposure to contaminants than farmed fish, which can contain additives, antibiotics, and more environmental pollutants,” Carli explains. While this is often the case, responsible farm fishing can be done in a way that doesn’t result in off-the-charts contaminant levels (be sure to do your research), and not all wild-caught fish are necessarily considered sustainable. In fact, over 90 percent of global fish stocks are either over-fished or even completely exhausted. 

When looking to buy more sustainable wild-caught fish, be sure to inquire about the method of catch. Pole-and-line-caught, pole caught, school caught, troll-caught, FAD-free, and free school all signify that the fish was caught in a way that minimally impacted surrounding marine wildlife, through the avoidance of large wall netting responsible for species loss due to bycatch.

Opting for fish lower on the food chain can also be a wise option. “Fish lower on the food chain have fewer toxins (like mercury and PCBs) because they eat fewer (if any) contaminated fish, making them a safer choice,” Carli adds. Fish higher on the food chain eat fish who have eaten other fish before them, resulting in greater and greater contaminant build-up in their systems (and flesh). Additionally, fish lower on the food chain tend to be more sustainable options, as they have a shorter lifespan and reproduce quickly which lends their cultivation to having a lower environmental impact on ocean ecosystems.

7 of The Healthiest Fish Varieties 

Given this slew of information, we’ve teased out seven types of fish that tend to be healthier, lower in impurities, and more environmentally-sound than the rest.

Sardines

While many foodies may already have a tin of sardines sitting in their pantry, they’re more than worth a try if you’ve never had them before. “These small fish are packed with omega-3s, calcium, and vitamin D. I love serving them in pasta dishes, or sauteing them with aromatic veggies at the beginning of a stew to provide extra flavor.” says Carli. Sardines also make for a delicious tuna-like seafood salad for sandwiches, crackers, or as a salad topper.

Mackerel

Another common fish you’ll find in the canned foods aisle is mackerel. This fish is lower on the food chain, like sardines, making it an option that is bound to be lower in mercury and other contaminants. “Mackerel is high in omega 3 fatty acids, and best enjoyed smoked, grilled, or tossed with vinaigrette in salads,” Carli explains. This oily, rich fish is also super tasty in tomato-based pasta recipes, and can even be made into delicious fish cakes.

Salmon

As one of the most quintessential healthy fish choices, salmon does have a lot to offer nutritionally—as long as it’s caught responsibly. “High in omega-3s and vitamin D, salmon is versatile and has a mild flavor,” Carli agrees. While she loves to roast or grill salmon marinated in lime juice and sriracha or a BBQ rub, this beautiful pink fish is also delicious in salads, pastas, fish tacos, and tray bakes. Plus, canned salmon is an accessible option that still boasts fantastic flavor in fish cakes or seafood salads.

Herring

When choosing fish low on the food chain, herring is one of your best choices as a small, quickly reproducing seafood option. “Herring is high in omega-3s and vitamin B12, and is usually available pickled or smoked,” Carli offers. However, herring is also commonly available canned, and is scrumptious served atop whole grain crackers, in a Scandinavian-inspired salad, or sauteed with aromatics. And if you happen to stumble upon fresh filets, it doesn’t get much better than panko-crusted, shallow-fried herring.

Rainbow Trout

As a sought-after catch for fly fisherman, rainbow trout is a beautiful fish to behold, with colorful iridescent skin and dark orange, salmon-like flesh. While not as low on the food chain as other options on this list, “this mild, omega-3-rich fish is lower in contaminants than other high food chain fish because of its middle-of-the-road standing,” says Carli. Rainbow trout is nothing short of *chef’s kiss* when pan-seared, roasted, or baked with garlic, herbs, and a sprinkle of chili flakes.

Anchovies

While anchovies often get a bad rap, they are not only deceptively delicious but have so much to offer nutritionally. Because you’re technically consuming their tiny bones when enjoying them, anchovies are an excellent source of calcium, as well as protein, omega-3 fatty acids, selenium, and B vitamins. These flavorful canned options are perfect in homemade Caesar dressing, pasta puttanesca, brothy beans, sauces, and even marinades.

Cod

And finally we have cod, a white flakey fish. If you didn’t grow up on the east coast of the country, then you might not be as familiar with this fish, but boy is it worth getting acquainted with. “Lean, mild, and a good source of protein and B vitamins, cod is excellent baked with a sprinkle of paprika, or in a light tomato-based stew,” says Carli. As a “middle-of-the-road” fish in terms of ranking on the food chain, cod will also be lower in contaminants than some of the top-tier fish, like tuna.

How to Shop for in Healthy Fish

While this list is a great jumping-off point for purchasing healthier seafood, there are many more options that fit within these parameters. With these general rules of thumb, you can feel confident in your ability to find them when perusing the fish counter and canned fish aisle:

• Opt for smaller fish lower on the food chain for maximum nutrition and lower levels of contaminants
• Steer clear of pre-breaded and fried fish to avoid unnecessary sodium, saturated fat, and additives
• Scour food packaging (or ask your fishmonger) for information on method of catch and sustainability of a given product
• Keep an eye out for fish that have been third-party tested for mercury levels
• Look for keywords like pole-and-line-caught, pole caught, school caught, troll-caught, FAD-free, and free school for more sustainable wild fish
• Minimize how often you’re eating fish that top the food chain, like swordfish, tuna, and marlin, to avoid high levels of mercury and contaminants
• Use resources like Seafood Watch to research fish you’d like to purchase