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In this Lesson you will Learn

  1. What are the most sustainable fish?
  2. Should you buy wild caught or farmed fish?
  3. Which fish contain high levels of mercury?
  4. How to tell when fish is done

Fish is extremely healthy and is eaten frequently in many of the world's healthiest diets. You can reap the health benefits of eating fish by eating fresh, frozen, smoked, or canned fish.

Fresh fish should look and smell, well, fresh! If you are buying whole fish, make sure the eyes are bright and clear and the gills a rich red color. Fillets should not be dull-looking and the skin, if still attached, should shine.1

It is also important to pay attention to which species you buy and where they came from. Many species of fish are overfished, so it is important to choose sustainable choices by referring to sustainable seafood guides.2

When it comes to farmed versus wild caught fish, here's what you need to know: wild caught fish is not necessarily healthier than farmed fish, in fact, it could even be the other way around as farmed fish has been shown to have more omega-3 fatty acids!3 Wild caught fish is not necessarily more sustainable either, as both fishing and farming practices can be destructive when not done properly. 

All in all, there are good and bad choices when it comes to farmed and wild caught fish. We recommend consulting the guide above to find sustainable species and then choose wild or farmed depending on what you have access to. If you're buying farmed, it is definitely advisable to choose farmed fish from the US or EU. Farmed fish from Asia has been shown to contain more antibiotics and other contaminants.4

Another concern is mercury levels. To be on the safe side, avoid swordfish, king mackerel, orange roughy, and most tuna.5

Now that you've bought your fish, how should you prepare it? Many chefs will tell you the most common mistake people make when preparing fish is overcooking it. Since fish will continue to cook once it has been removed from the heat, you should take it off when it has just lost its translucency. The tip of waiting until the fish flakes is unfortunately not the best advice—it will likely be too dry already.6 Instead, the fish should be firm but not quite flaky yet.

Again, if you live some place where fresh fish is not plentiful, frozen, smoked, and canned fish are great alternatives.

Nutrition DNA

The nutrition DNA of fish. For example, you can see that 100g fish covers 60% of your daily need of Selenium and 41% of the recommended Protein intake. Hover over the bars to see which nutrient is covered.


  1. Fish Cooking
  2. Seafood Watch
  3. Quick and Dirty Tips - Farm Raised vs Wild Caught Fish
  4. - How safe is your imported seafood
  5. Quick and Dirty Tips - Should you be worried about mercury in fish
  6. Fine Cooking - How to tell when fish is cooked


  1. Refer to sustainable seafood guides to find out which species are best to buy.
  2. Both wild caught and farmed fish can be good options if you buy sustainable species and avoid farmed fish from Asia.
  3. Fish with high levels of mercury: swordfish, king mackerel, orange roughy, tuna
  4. Fish is done when it loses its translucency and is just about ready to flake.
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