Want To Be Healthy? Avoid These 7 Toxic Fish

This fish looks fresh and delicious but looks can be deceiving. It could contain high levels of mercury

How to Prevent Your Greatest Risk for Toxic Mercury Exposure

Living Better Series Part 1: Avoiding Toxic Mercury

Are you feeding your children poisonous chemicals? 

If you're pregnant, are you consuming toxic substances that could injure your fetus?  

Do you eat dangerous toxins?

Of course not! Or, rather, not on purpose.

But, if you're eating fish, on a regular basis, you could be doing just that. You could be exposing yourself to the number one risk for toxic mercury - eating fish.

Many species of fish have excessive levels of toxic mercury. And, unless you know which fish are safe to eat you could be consuming dangerous amounts of mercury or feeding it to those you love. In this article, we'll cover everything you need to know - to protect yourself and your family. At the end of the post you'll find several useful resources.

Eating harmful food or feeding it to your children, without knowing, is a terrifying thought
— Anna, mother of two children, age 3 and 6 months

Risky Fish Business

There are seven types of fish that young children and pregnant or breastfeeding women should avoid. These fish are risky because they can contain high levels of toxic mercury.

Mercury is ubiquitous, it's in our air, food, and waterways. Almost everyone has a trace of mercury in their body. Thankfully, the amount is usually too low to cause health problems.

Several decades ago, before it was discovered that mercury was poisonous, it was used in a lot of products. Remember mercury thermometers? You may still have one lying around your house. What about Mercurochrome? It was used as an antiseptic and it contained mercury. "Monkey blood", as children called it, was found in most medicine cabinets. That is, until, it became non-existent in the U.S. It's not banned, but no one's making anymore for use in America.

But, these days, you're more likely to be exposed to mercury by eating fish. The purpose of this post is to help you to make better educated decisions about the fish in your diet. At the end, you'll find several useful resources to keep needed information readily at your fingertips.

Mercury doesn't affect the fish but it can be dangerous to humans if ingested or inhaled.

Mercury doesn't affect the fish but it can be dangerous to humans if ingested or inhaled.

How Does Toxic Mercury Get Into Fish?

The source of the most mercury in marine life comes from coal burning plants. The start of the cycle is, primarily, from those industrial factories that spew air pollution from their smokestacks. The gases travel, in wind currents, thousands of miles, all over the planet. It, then, falls as precipitation into the world’s lakes, rivers, and oceans.

The mercury falls from the air and is first absorbed by the smallest creatures of the sea. They, in turn, are eaten by bigger marine animals and so on. As it moves up the food chain, the amount of mercury in the fish increases - along with the size of the fish. By the time is gets to the larger fish, like tuna or sharks, the mercury can reach high levels.

Fish is a common food staple in many countries around the planet, including the Americas. The annual per capita consumption of fish has grown steadily. Studies of the world's waterways have shown that mercury levels in fish continues to rise at a rapid rate.

There's a desperate need to clean up our bodies of water which will take a major global effort. And, its not happening fast enough. But, until conditions improve,  you need to know how to protect your health and that of your family.

So, for now, the question remains - how can we enjoy eating fish and stay safe? 

What goes up, must come down. What goes up in the air comes down into the world's waterways.

What goes up, must come down. What goes up in the air comes down into the world's waterways.

Can Mercury Poisoning Be Treated or Cured?

Mercury doesn't provide any health benefits to our body like other elements. Read the label on your multivitamin bottle. You'll see a long list of elements and metals your body needs. But, you won't see the mercury in any supplement. Its a neurotoxin. This means too much of it can damage the brain and nervous system. It can also harm the kidneys. A growing fetus and young children are highly susceptible to it's effects because their nervous systems are still developing and, thus, easily damaged. Those with weak immune systems and the elderly are equally at risk.

Some of the signs of neurotoxicity are dizziness, anxiety, numbness, tingling sensations, hallucinations, headaches, muscle weakness, lack of coordination and tremors.

Once neurological damage has occurred, unfortunately, its irreversible. There are treatments but they mainly decrease the amount of mercury in the body and prevent further damage. Usually, once mercury has accumulated in the body, the goal is to eliminate any further exposure, since it remains in the tissues for a lifetime.

Mercury is Silent and Sneaky!

  • It has no taste, 
  • Heat, or cooking, doesn't destroy it,
  • The skin of the fish doesn't protect its meat from mercury. Meaning, you can't remove the skin to make the fish safer to eat like you might for fried chicken or by peeling a vegetable to prevent pesticide exposure.
  • Without a specific blood test, most people are unaware their mercury level is high.
  • You may not know you're accumulating large amounts of mercury until symptoms begin. Unfortunately, others find out when a baby is born with nervous system problems.

Why Is The Mad Hatter...Mad?

You've probably heard the terms the “mad hatter” and “mad as a hatter”. Most of us associate it with the character in the Lewis Carroll classic Alice in Wonderland. But, do you know where that saying originated?

Of course, the theme of this post is a huge hint. You guessed it - mercury poisoning. So, here's a bit of history and the origin of the phrase.                                                                                                                                  

The Hatter from Alice in Wonderland by Lewis Carroll. Everyone in wonderland may have been mad but it wasn't due to their hats.

The Hatter from Alice in Wonderland by Lewis Carroll. Everyone in wonderland may have been mad but it wasn't due to their hats.

The character was, actually, called "The Hatter".  Somewhere, over time, we began to refer to him as the "Mad" Hatter. The storyline is that everyone in Wonderland, including the Hatter, was, supposedly, mad. As the Cheshire Cat said to Alice about Wonderland ..."we're all mad here. I'm mad, you're mad". 

A “mad hatter’ or the ‘mad as a hatter’ phrase began as a reference to problems troubling hat makers in the 1800’s. Mercury was part of a solution used to turn fur into felt for fashioning hats. Poor ventilation, in factories and workshops, caused the hatters to inhale noxious mercury fumes, all day, while working.

We know, now, that mercury is highly toxic. But in the 1800’s no one, including the hatters, knew the danger of breathing mercury vapors.
— Neurologist, age 60

The unlucky hatters, who absorbed so much mercury, began to exhibit trembling known as the “hatters shakes”. They also experienced memory loss, irritability, uncoordinated movement, slurred speech and other signs we know as mercury poisoning. It wasn't madness or mental illness. Later, Mad Hatter Syndrome began to refer to mercury toxicity.

A more professional term is Minimata Disease or Chisso-Minimata Disease. The name comes from Minimata, Japan. Its citizens developed mercury poisoning from polluted wastewater from the Chisso Corporation. The mercury rich water was dumped from factories into local waters and absorbed by fish. Fish was a big part of the diet of the Minimata citizens and soon large numbers of people, cats and dogs began to exhibit symptoms.

If you're concerned about other sources of mercury that you and your family may be exposed to - check out the Living Better Series Part 2 article about the mercury in your mouth as dental fillings HERE.

But I don’t want to go among mad people, Alice remarked.
Oh, you can’t help that, said the Cat: we’re all mad here. I’m mad, you’re mad.
How do you know I’m mad? said Alice.
You must be, said the Cat, or you wouldn’t have come here”
— The Cheshire Cat, "Alice in Wonderland" by Lewis Carroll

The sushi bar at Nobu Miami. Amazingly delicious and healthy fish! Remember, freshness doesn't matter in the case of high mercury fish.

The sushi bar at Nobu Miami. Amazingly delicious and healthy fish! Remember, freshness doesn't matter in the case of high mercury fish.

How To Protect Your Yourself Against Mercury in Fish

How can you choose fish that is, both, healthy and safe to eat?  The number of fish species found in menus and supermarkets is endless and overwhelming.

The federal government, through the U.S. Federal Drug Administration and Environmental Protection Agency, recently, issued new guidelines that can help in making good decisions. To make it, even easier to choose healthy edible fish, I summarized the long FDA report and put it into a chart. It's printed in the post below or you can download a free copy. There's also a great chart in the FDA report HERE

 In addition, I've included another fantastic resource from the Monterey Aquarium below.

 FDA Categories of Edible Fish

The FDA has grouped edible fish into 3 groups signifying the level of health choice from "best" to "avoid". Their categories are:
1. Best Choices
2. Good Choices
3. Choices to Avoid

 The 7 Fish to Avoid Due to High Levels of Mercury

  • Shark
  • Swordfish
  • Orange roughy;
  • Bigeye tuna;
  • Marlin; 
  • King mackerel;
  • Tilefish from the Gulf of Mexico

*Before eating any locally caught fish, check with the local fish advisory. If you can't get information then eat locally caught fish, only, once a week.

See how to download a free copy of this chart below.

See how to download a free copy of this chart below.

I've visited the Monterey Bay Aquarium. If you're in the area, it's one place you shouldn't miss.

I've visited the Monterey Bay Aquarium. If you're in the area, it's one place you shouldn't miss.

Another Fantastic Resource For Choosing Safe Fish to Eat

Check out the free app from the Monterey Bay Aquarium called Seafood Watch, available on both iTunes and Google Play.

From the convenience of your smartphone or laptop, you can search types of seafood that’re healthy to eat. It's a breeze to use in a grocery store or restaurant. The app sorts choices into best, alternatives and what to avoid. It will even give you the Japanese names for fish. That's a blessing when you're trying to translate a sushi menu. You can find the app HERE at iTunes and HERE at Google Play.

The Monterey Bay Aquarium also publishes a "Super Green List" - that's the uber good fish to eat list. It names the 5 fish that have a whopping 250 milligrams of omega-3 fatty acids and very low levels of mercury.

And Speaking of Sushi... And not Speaking of Mercury!

We've said children, under age 6, and pregnant women should be extra careful to choose fish from the Best Choices category. But, there is another important recommendation from the FDA included in the 2015-2020 Dietary Guidelines for Americans. Thats the restriction warning pregnant women and young children not to eat any species of raw fish. For information on food-borne illnesses see my post on food safety issues in the U.S. home meal delivery kit programs.

And Now For Some Good Fish News...Finally!

The good news is that 90% of fish we eat, in the U.S, falls into the “best choices” category. Because of the beneficial nutrients found in fish, the FDA encourages pregnant women and growing children to eat more cooked fish.

In a recent survey, the FDA found that half of pregnant women ate less than 2 ounces of fish a week. This is far less than the 8 to 12 ounces, or 2 to 3 servings, per week recommended for healthy growth and development of the fetus during pregnancy. Children should eat a variety of fish types, one to two times a week, with the amount depending on the age and weight of the child. See my free chart HERE for a quick estimator of portion size as well as the safe fish list.

Wouldn’t you know... there is no suggested limit for men as to the amount of fish they should eat. As a result, men and non-childbearing women can eat fish in the “avoid”, or highest mercury category, but only once a week.

Why would anyone eat fish from the "avoid" category?

If you eat tuna then you're a person that chooses a potentially high mercury fish. Tuna is a popular dish found in an endless number of restaurants. If you love tuna, remember to limit your intake.

It's always better to choose the safer types of fish. Try to concentrate, in particular, on fish that are low in mercury and high in omega-3 fatty acids. See the Monterey Aquarium's Super Green List.

More Questions About Keeping Fish In Your Diet

1. Why Should I Eat Fish?

Hopefully, this post has given you the knowledge and confidence you need to eat fish safely. But, maybe, you're still skeptical and wonder why you should eat fish at all?  Why not stay on the safe side?

Fish is delicious AND full of nutrients. Pregnant women and growing children can benefit by eating a healthy diet that includes fish… the healthy kind

Something's Fishy


  • Fish is high in healthy omega-3 fatty acids, particularly oily fish.
  • Fish is low in the bad type of fats, the omega-6 fatty acids.
  • The omega-3 fatty acids, in fish, improve blood clotting and blood vessel health.
  • Consuming good fatty acids helps the healthy development of child and fetal nervous systems.
  • A diet of fish improves tissue inflammation.
  • Eating fish has been shown, in studies, to improve the symptoms of rheumatoid arthritis. You can read some research on fish and RA HERE.
  • Eating fish may slow mental decline in the elderly.

2. Do The Benefits of Eating Fish Outweigh the Risk?

Marine creatures are the best source of omega-3 fatty acids by weight. You'd have to eat a lot more of other, omega-3, sources to get the same benefits you get from one piece of fish. And, since most of the fish we consume is in the Best Choice Category, it's easy to reap the health benefits of eating fish.

Use available resources, like downloading my free chart BELOW or the FDA chart HERE or the Monterey Aquarium app HERE at iTunes or Google Play HERE. With these resources, it’s easy to know which fish you can safely enjoy.

So, go for it, if you love fish!

3. Why Eat Fish? Why Not Take A Fish Oil Supplement Instead?

Make sure you choose a high quality brand if you choose to take a fish oil supplement.

Make sure you choose a high quality brand if you choose to take a fish oil supplement.

Over the counter fish oil supplements are made from the same fish we eat. But, they may, also, come from fish used for fish food, not human food. Toxic substances can be present in fish oil just as they can be present in fish.

Therefore, it's important to buy a high-quality product from a reputable company. Make sure you buy capsules that are made from “purified fish oil”. Check with your pharmacist if you need a recommendation.

4. What're Other Sources Of Omega-3s I Can Add To My Diet? 

Flaxseed, walnuts, canola oil, wild rice, eggs, soybeans, enriched dairy products and wheat germ are good sources of the best type of fatty acids. But, studies show that health benefits of fish, shellfish, and marine algae are their greater omega-3s by weight. That's a lot of wheat germ as opposed one serving of seafood. 

Final Thoughts On Living Better by Eating Healthy

I'm blessed to live in an area where there's an abundance of great seafood. In Louisiana, we have crawfish, oysters, crab, shrimp and many types of fresh and saltwater fish.

We grow up fishing and crabbing in the Gulf of Mexico and our multitude of bayous and rivers. What we caught was, often, cooked and eaten right away. But, today, diligence is important no matter how fresh the fish and no matter where it’s caught. 

Mercury levels, in fish, have increased significantly everywhere. Those innocent days are long gone. Be concerned about the safety of locally caught fish. The best recourse is to check with the area's fish advisory.

If you can't get needed information, your best option is to restrict eating locally caught fish to once a week. You can locate an area's fish advisory on the internet. Research the wonderful information available from those advisories. They also publish swimming advisories! View the helpful site for Louisiana HERE.

To find more useful nutrition information for LIVING BETTER - read the article on myths vs. facts found in nutrition HERE. For more knowledge about mercury exposure, see Part 2 on safety concerns and the mercury in dental fillings HERE.

Related Posts

  1. You Need to Forget These 5 Nutrition Myths
  2. Do You Know if You Have Toxic Mercury in Your Fillings

We'd love to hear your thoughts about mercury levels in fish. Also, let us know your recommendations for restaurants with great, fresh fish dishes? Put your ideas in the Comment Section below.

Stayed tuned for Part 2 of the Avoiding Toxic Mercury series. In it, we cover the safety of mercury in your mouth....as dental fillings. You can read that post HERE

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