When it comes to excellent protein sources, fish are pretty hard to beat. As your plate’s main event, or as an accent in soups and salads, fish is one of those tasty, health-supportive go-to’s that should make it into your rotation 2 - 3 times a week - that is, as long as you’re eating the right stuff. As with all foods you eat on the regular, to extract maximum benefits, quality matters, and when it comes to fish, you’ll need to be on the lookout for seafood that’s as clean, sustainable, and kind to the planet as possible. To cover these essential bases, here’s where to start, why you need to, and what to eat, what to avoid:

Good fish makes for a happier heart.

First up, eating fish is an excellent way to stock your body with protein, nutrients, B vitamins, vitamin D, zinc, iron, magnesium and potassium. Creatures of the sea, and more specifically the types often referred to as ‘oily’ or ‘fatty fish,’ are particularly good food-based sources of omega-3 fatty acids, the beneficial fats that can help lower blood pressure, reducing the risk of heart attack and stroke. What else can those omega-3s do for you? According to the Cleveland Clinic, quite a bit:

• Reduces the risk of blood clots; omega-3 fatty acids help prevent platelets in the blood from clumping together.
• Keeps the lining of the arteries smooth and free of damage so plaque doesn’t form which can lead to thick, hard arteries.
• Slows down the production of triglycerides in the liver, lowering levels in the blood and decreasing the risk of heart disease.
• Decreases inflammation. Substances released by the body’s inflammatory response can contribute to atherosclerosis (hardening of the arteries). Omega-3 fatty acids tamp down their production.

Fish gives your brain lots of TLC.

Thanks to those all-important omega-3s, namely EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), fish supports brain health and may decrease the risk for depression and ADHD, among other conditions.  A regular fish habit may also offer some protection against the neurological problems we fear most, like Alzheimer’s and dementia. Since our bodies don’t actually make their own omega-3s, eating foods rich in them, like fish, is the best way to get your fill. Granted, there are legitimate concerns about potentially toxic mercury levels. But it is possible to eat fish wisely enough to maximize the brain and body benefits, while minimizing many of the downsides. If you’re not a fish-eater, you can get omega-3s from eggs, walnuts and flaxseeds, and liquid fish oil, or, better yet, a high-quality fish or krill oil (in pill form), containing at least 1000 milligrams of DHA and EPA.

Get real about your fish.

While eating fish is a great way to get a regular dose of protein and those heart-protective omega-3s, you do need to eat the healthiest fish possible. Trouble is, most people don’t. They’re eating the aquatic equivalent of junk food, and by that we mean fish produced by the ‘farmed’ fishing industry, whose mission it is to grow more fish, faster, larger and as cheaply as possible. Similar to factory-farmed meats, what winds up on your plate is protein from creatures that have been raised on low-quality feed; spent much their lives packed ‘to the gills’ in filthy, over-crowded tanks, stressed out and sick; and fed multiple rounds of antibiotics – hardly a recipe for a nutritious, quality product. By some estimates, farmed fish can deliver up to 20% less protein, twice as much inflammation-boosting omega 6 fatty acids, less usable omega 3s and fewer nutrients overall – so you get what you pay for. Cheap, irresponsibly farmed fish comes at a price – one that winds up polluting not only your body but also the bodies of water from whence the fish came. Is that a trade-off you can feel good about? Didn’t think so.

Buy fish with a pedigree.

Wild fish, however, offer more protein and nutrients than farmed, plus a healthier ratio of omega-3s to inflammation-triggering omega-6s, making wild the healthier choice. To minimize your contribution to the problem of over-fishing, when buying, choose certified wild fish, preferably pole-caught. Bypass the farmed stuff and look for companies that practice sustainable and eco-friendly fishing techniques. Also be conscious about type of fish you choose —the fattier the fish, the more important it is for you to buy from a quality source, as both nutrients and toxins accumulate in the fat. Though a percentage of contaminants may be reduced by cooking (the heat melts some of the tainted fat), mercury does not cook off. So, instead of stockpiling any old seafood item on super-sale at the supermarket, buy smaller quantities of healthier fish from specialty providers, like vitalchoice.com and sea2table.com.

Don’t be frightened of fish – be conscious of them – and do your research.

OK, so let’s face it, with fish, more is not necessarily better. Going hog-wild on the stuff and eating it daily – no matter how pristine your fish might be – is not healthy for you or our oceans, so manage your dose. And while threat of contamination is real, your mission is not to be frightened of fish, but to be conscious about the ones you put in your body. To navigate the wild world of fish in a way that supports both your body and the ocean, our go-to sources of aquatic wisdom include:

• The Monterey Bay Aquarium’s fantastic web site Seafoodwatch.org idiot-proofs the fish shopping process with a comprehensive list of the 50 must-avoid types of fish most commonly offered at your local supermarket. Download the app to make fish shopping a breeze.
• The Environmental Defense Fund’s Seafood Selector comprehensive site ranks the average mercury levels in hundreds of fish species, their ecological impact, and includes helpful recommendations on how often you should or shouldn’t partake.
• The Vancouver Aquarium’s Ocean Wise 2020 Guidelists thousands of species of fish, with recommendations on sustainable versus unsustainable choices, harvest methods, regions, and fishery names.
• Also look for the seal of approval from the Marine Stewardship Council, a watchdog group that tracks catch methods, fisheries practices and monitors fish populations for over-fishing.
• When dining out, cross-check what’s on the menu against FishChoice.com, which verifies that the fish served at participating restaurants is sourced from sustainable fisheries.

Think small, think oily.

There is a lot to think about when buying and eating fish, but if you remember nothing else, smaller is better. Small, cold-water fish like sardines, anchovies, herring and mackerel are much safer to eat than large fish like tuna, bluefish, blue and striped marlin, grouper, swordfish or shark, which can grow to hundreds of pounds, accumulating more mercury and other toxins as they age. The little fish, by virtue of their smaller size (just a few ounces) and shorter lifespans don’t have the same accumulation problem – so always think small, and tuck into a fish-centric meal no more than 2 or 3 times a week. Other points to keep in mind:

• If you like your fish canned, always look for BPA-free cans, and if you have a choice, opt for sockeye or wild Alaskan salmon which delivers less mercury, and more omega-3s and vitamin D than canned tuna.
• Look for ‘pole and line-caught fish,’ a method which catches one fish at a time vs, the extremelydestructive ‘gill-net’ fishing that catches and kills just about every marine creature in its path.
• If a canned tuna is your thing, one serving a week is plenty, and stick to the smaller skipjack kind which has roughly three times less mercury that albacore. Click here for Greenpeace’s in-depth canned tuna guide.
• Last but not least, when it comes to shrimp, even though it is a small sea creature, avoid the imported shrimp at all costs, as it’s almost always farmed overseas in virtually unregulated, extremely unhealthy and ecologically destructive conditions.