8 fish that can contain high levels of mercury

Some fish have higher levels of mercury than others.

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Some fish have higher levels of mercury than others.
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Shutterstock

  • Some fish are higher in mercury than others.
  • You should avoid fish high in mercury if you’re pregnant or nursing.
  • The FDA recommends avoiding fish like marlin, shark, and tilefish.
  • But it can depend on where you live and the exact type of fish.
  • Visit INSIDER’s homepage for more stories.

Fish can be a healthy and delicious meal, but if you’re fish fan, you may be concerned (and even a little confused) about mercury levels in your fish.

To be clear, all fish contains some amount of mercury. Some people should be more worried about mercury than others, including pregnant people, people who are nursing, and children. We rounded up some recommendations from the FDA of fish you should consider avoiding because of their high mercury levels.

Just a note that where you live and how a fish is raised and caught can play a factor in its mercury levels. It’s important to do your research before buying and consuming fish.


King mackerel starts off the list.

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King mackerel
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Wikimedia Commons

King mackerel is a medium-sized fish with a strong taste that can contain high levels of mercury, according to the FDA.

But not all mackerel should be avoided: Atlantic mackerel is actually on the low-end of mercury levels, according to the FDA, and can be a great alternative.


Marlin can contain higher levels of mercury because of its place on the food chain.

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Marlin.
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Shutterstock

Marlins are bigger fish that eat lots of little fish and therefore ingest the mercury inside them and make their mercury levels higher, according to PBS. And they’re not the only ones.

“Sharks, marlin, polar bears and people at the end of the food chain have the highest concentration of mercury,” Tim Fitzgerald, a marine scientist for Environmental Defense Fund, who provides health consumption information to Monterey Bay Aquarium’s Seafood Watch, told PBS.


Orange roughies suffer from over-fishing and contain higher levels of mercury.

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Orange roughy.
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Shutterstock

These fish roughy have a longer lifespan than many other types of fish, which can make their mercury levels higher, according to SF Gate. In fact, they can live up to 149 years, according to Smithsonian.

This fish also suffers from over-fishing, according to the Smithsonian, so if you’re concerned about sustainability, it could be one to avoid for that reason, too.


Sharks are another big fish that eats little fish.

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A great white shark.
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Shutterstock

Sharks are known predators who are another fish that gets its high mercury levels from ingesting other smaller fish.

In fact, mercury levels in sharks can be two to six times the recommended maximum for human consumption, according to a small 2011 study of sharks in New Jersey.


Swordfish is a mild fish that the FDA said should still be avoided.

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Swordfish being prepared.
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Flickr/Keith McDuffee

Many tout swordfish as a milder fish, great for those who aren’t sure if they like seafood. It also can be high in mercury, making it not the best option for everyone.

If you’re looking for a mild fish alternative, shrimp and whitefish can be good choices that are lower in mercury.


Tilefish is not recommended depending on where you are.

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Tilefish.
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Jun Seita/Flickr

Tilefish remains on the FDA list for high levels of mercury, but it’s worth noting that some states like South Carolina have scaled back on their advisory for the fish in the past.

As always, these regulations can change based on where you are and where you get your fish, so it’s always best to do your research.


Some types of tuna make the list.

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Ahi tuna.
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kitzcorner/Shutterstock

In one of the more confusing entries on the list, big-eye tuna is on the FDA’s watch list for high mercury levels. Other tunas like ahi tuna make the watch list for organizations like the Natural Resources Defense Council for their mercury levels, too.

However, some other variations of the fish like Skipjack tuna are actually recommended by the FDA due to its typically low mercury levels.


Any fish that is caught by you or someone you know may contain high amounts of mercury.

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Fish you catch yourself may contain high levels of mercury.
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Rocksweeper / Shutterstock

If you or your loved ones are prone to catching your own food, the FDA warns that these fish can contain unknown amounts of mercury, even if the fish isn’t on this list.

The FDA suggests checking for local advisories and if there aren’t any, you can safely eat that fish, but should avoid eating fish for the rest of the week.