A beginner's guide to buying fish

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A Beginner’s Guide to Buying Fish That’s Actually Good for You

Buying fish sounds easy. You walk into the shop, point to what looks fresh, and that’s it. But here’s the thing — where your fish comes from and how it was raised can make a huge difference to your health. If you want to get all the benefits of eating fish without the hidden risks, there are a few secrets you should know.

Why the FAO zone on your fish label matters

Every package of fish sold in the EU and many other countries lists its FAO fishing zone, which is a numerical code telling you where it was caught. This is more than a technical detail; it’s your first clue about the fish’s safety and quality. Some zones are pristine, while others have known pollution problems from heavy industry, agricultural runoff, or even nuclear accidents.

One example is the Fukushima disaster, which released radioactive contaminants into the surrounding waters. While global monitoring has significantly reduced risk over time, awareness is still important. For those who want the full scientific background, you can read the official WHO & FAO report Impact on Seafood Safety of the Nuclear Accident in Japan here, which also contains the Map of Major Fishing Areas and their numbers. It details how contamination spreads, which zones are monitored, and what this means for seafood safety today.

Wild vs farmed salmon — more than just the color

One of the easiest ways to tell wild salmon from farmed is by the color. Wild salmon gets its deep reddish-orange flesh from eating krill and shrimp, which are rich in astaxanthin, a natural antioxidant. Farmed salmon is usually paler, so fish farms add synthetic astaxanthin to their feed to make it look more like wild salmon.

But the bigger issue is the fat profile. Wild salmon live in open waters and eat a natural diet, so they develop a healthy balance of fats. Farmed salmon is raised on grain-based feed, which is higher in omega-6 fatty acids and lower in omega-3s. This means that even though farmed salmon might have more total fat, the quality of that fat is not the same.

Why the omega-3 to omega-6 ratio matters for your health

Our bodies need both omega-3 and omega-6 fatty acids. They are essential fats, meaning we cannot make them ourselves and have to get them from food. The problem is balance.

Scientists believe that during the Paleolithic era, humans ate a diet with an omega-3 to omega-6 ratio of about 1 to 4. That balance kept inflammation in check and supported brain and heart health. Today, in places like the United States, the ratio has shifted to about 1 to 20 — heavily in favor of omega-6.

Why is that bad? Omega-6 fatty acids, in excess, can trigger inflammation in the body. Chronic inflammation is linked to everything from heart disease and arthritis to skin problems like acne and eczema. Omega-3s, on the other hand, are anti-inflammatory. They help keep your heart healthy, your brain sharp, and your skin glowing.

When you eat farmed fish that has been raised on grains instead of its natural diet, you are getting a much higher dose of omega-6 compared to omega-3. Over time, this pushes your ratio in the wrong direction and works against the reason you might be eating fish in the first place.

How to make the healthiest choice when buying fish

If wild fish is hard to find, there are still ways to make a good choice:

Check the FAO zone on the label and avoid fish from heavily polluted waters

Choose species that naturally have high omega-3 content like wild salmon, sardines, mackerel, and herring

If you must buy farmed fish, look for producers who feed their fish a more natural diet and avoid overcrowded pens

Ask your fishmonger when the fish was caught and how it was stored

The bottom line

Fish can be one of the most nourishing foods you eat, but only if chosen carefully. Knowing how to read FAO zones, understanding the difference between wild and farmed, and paying attention to your omega-3 to omega-6 balance can help you enjoy all the benefits of seafood without the hidden health risks. Think of it as not just buying dinner, but investing in your long-term health.