14 Fish You Should Consider Never Eating

Fish is often considered one of the healthiest sources of protein, rich in omega-3 fatty acids, vitamins, and minerals. But not all fish are created equal. Due to overfishing, contamination, and unsustainable farming practices, some fish pose serious risks to your health and the environment. Whether it’s due to high mercury levels, toxins, or destructive harvesting methods, here are 14 fish you should consider avoiding—or eliminating—from your plate entirely.

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1. Shark

Sharks are apex predators, meaning they accumulate high levels of mercury over time. Mercury poisoning can affect the nervous system, especially in pregnant women and children. Plus, shark populations are rapidly declining due to overfishing and finning.

2. Swordfish

Swordfish are known for their firm texture and rich flavor, but they also carry dangerously high levels of mercury. Health organizations, including the FDA, recommend children and pregnant women avoid it entirely.

3. Tilefish (Gulf of Mexico)

Tilefish from the Gulf are among the most contaminated fish in U.S. waters, with mercury levels that can be harmful to humans. Even occasional consumption is discouraged.

4. King Mackerel

This large mackerel species is another mercury-heavy fish. It’s especially dangerous for young children and expecting mothers. Opt for Atlantic mackerel instead, which is lower in contaminants.

5. Orange Roughy

Often marketed as a delicacy, orange roughy can live up to 150 years. Unfortunately, that longevity also means they accumulate toxins like mercury over time. They’re also severely overfished.

6. Bluefin Tuna

Prized in sushi restaurants, bluefin tuna is critically endangered due to overfishing. It also contains high mercury levels. Choosing sustainable alternatives like skipjack or albacore tuna is a better option.

7. Eel (Unagi)

Freshwater eel is a popular delicacy in Japanese cuisine, but it’s high in PCBs (polychlorinated biphenyls) and often sourced unsustainably. Wild populations are dwindling due to habitat loss and overfishing.

8. Chilean Sea Bass (Patagonian Toothfish)

This deep-sea fish is prized for its buttery flavor, but most of it comes from illegal or unregulated fisheries. It also contains elevated mercury levels. If you must eat it, look for Marine Stewardship Council (MSC) certification.

9. Farmed Salmon (Especially Atlantic)

Farmed salmon can be high in contaminants like PCBs and dioxins. They are often raised in crowded pens, treated with antibiotics, and fed unnatural diets. Wild-caught Alaskan salmon is a healthier, more sustainable choice.

10. Imported Catfish

Many imported catfish come from countries with lax regulations on antibiotics and food safety. These fish may be exposed to harmful chemicals and pesticides not approved for use in the U.S.

11. Atlantic Cod

Once a staple in American and European diets, Atlantic cod populations have plummeted due to overfishing. Today, it’s a symbol of poor fishery management and environmental neglect.

12. Grouper

Grouper is susceptible to ciguatera poisoning, a foodborne illness caused by toxins found in certain reef fish. Additionally, many grouper species are overfished and slow to reproduce.

13. Imported Shrimp

While technically not a fish, imported shrimp deserves a spot on this list. A majority comes from countries with questionable farming practices, using antibiotics and harmful chemicals. Farmed shrimp can also damage coastal ecosystems.

14. Flatfish (Flounder, Sole, Halibut – Atlantic)

Many Atlantic flatfish species are overfished and caught using methods that destroy ocean habitats. These fish may also contain unsafe levels of mercury and other pollutants.

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Health Risks of Contaminated Fish

Eating contaminated fish occasionally may not harm a healthy adult, but regular consumption increases risks such as:

• Mercury poisoning (especially dangerous for developing brains)

• Cancer-causing toxins like PCBs and dioxins

• Antibiotic resistance from farmed fish

• Digestive issues due to parasites or poor handling

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What to Eat Instead

If you want to enjoy seafood without harming your health or the planet, opt for:

• Wild-caught Alaskan salmon

• Pacific sardines

• Rainbow trout (farmed in the U.S.)

• U.S.-farmed tilapia

• Mussels, clams, and oysters (which are low in contaminants and environmentally friendly)

Look for certifications like MSC (Marine Stewardship Council) or Best Aquaculture Practices (BAP) to guide your choices.

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Final Thoughts

Fish can still be a healthy part of your diet—but being selective matters. Environmental issues, contamination risks, and overfishing have turned some seafood options into health hazards. By avoiding these 14 fish and choosing sustainable alternatives, you’re not only protecting your body but also supporting the health of our oceans.