12 Unhealthy Fish You Should Avoid—and What to Eat Instead
Learn which popular fish are laden with contaminants, overfished, or unsustainable—plus healthier seafood swaps.
From mercury and toxic chemicals to overfishing and habitat destruction, not all seafood is created equal. While fish can be an excellent source of protein and omega-3 fatty acids, many commonly eaten fish pose health risks and contribute to ecological problems. This comprehensive guide examines 12 unhealthy fish to avoid, explains the science and environmental concerns behind each, and offers safer, more sustainable alternatives for your plate.
Table of Contents
- Why Avoid Certain Fish?
- 12 Unhealthy Fish to Avoid
- Better Seafood Choices
- Frequently Asked Questions
Why Avoid Certain Fish?
While seafood is often praised for its nutritional benefits, not all fish are equally good for your health or the environment. Key reasons some fish should be avoided include:
- Unsafe contaminant levels: Many fish accumulate harmful substances like mercury, polychlorinated biphenyls (PCBs), and other toxins.
- Severe overfishing: Excessive harvesting disturbs ecosystems and can push species toward extinction.
- Habitat destruction & pollution: Unsustainable farming or fishing can degrade water quality and destabilize marine environments.
- Seafood fraud & mislabeling: Incorrect fish labeling is rampant in the seafood industry.
Below, discover which fish rank among the dirtiest or most at-risk, plus tips for better seafood habits.
12 Unhealthy Fish to Avoid
Imported Catfish
Why it’s bad: The U.S. imports large amounts of catfish, particularly from Vietnam and China, where regulations for pharmaceuticals and chemicals are less stringent. Imported catfish may harbor banned antibiotics, pesticides, and heavy metal contaminants due to lax oversight. Less than 2% of imported seafood is actually inspected by authorities.
- Imported catfish are often labeled as “swai” or “basa.”
- Consumer Tip: Domestic, farm-raised catfish is generally a safer option.
Eat this instead: U.S. farmed catfish or other sustainably farmed white fish.
Caviar (Especially Beluga and Wild-Caught Sturgeon)
Why it’s bad: Caviar from beluga and wild sturgeon faces threats from overfishing and water pollution. These species take years to mature, making them slow to recover when depleted. Dams and industrial pollution also threaten their habitats, further endangering populations.
- Beluga, wild-caught, and Caspian Sea caviar are especially at risk.
- Conservation authorities have listed certain sturgeon as critically endangered.
Eat this instead: American Hackleback or Lake Sturgeon caviar from U.S. rivers, which are managed for sustainability.
Atlantic Cod
Why it’s bad: Once a vital food and economic resource, Atlantic cod populations have suffered from relentless overfishing. Today, stocks are so depleted that the species is listed as near-threatened and teetering above endangered status. Fisheries mismanagement has crippled both cod and the ecosystems dependent on them.
- The collapse of the cod fishery devastated Atlantic communities in the 1990s.
- Cod plays a crucial role in marine food webs now disrupted by its decline.
Eat this instead: Pacific cod, harvested from well-managed, healthier fisheries, is a suitable and sustainable alternative.
American Eel (Yellow or Silver Eel)
Why it’s bad: Popular in sushi and some regional cuisines, American eel contains high concentrations of mercury and PCBs, hazardous chemicals that accumulate in fatty tissue. International demand has led to overfishing and population decline, while pollution in their freshwater habitats worsens contamination.
- American eel is sometimes labeled as “unagi” in Japanese restaurants.
Eat this instead: Atlantic or Pacific calamari (squid) offers a similar flavor with fewer contaminants and is less threatened by overfishing.
Imported Shrimp
Why it’s bad: Shrimp is among the most consumed seafood in the U.S., with 90% being imported. Farmed shrimp from nations such as Thailand, Vietnam, and India are frequently exposed to antibiotics, pesticides, and cleaning chemicals. Insects, filth, and even bacterial contamination like E. coli have been discovered in imported shrimp. With minimal FDA inspection, these risks go largely undetected.
- Environmental impact includes mangrove destruction and water pollution from shrimp farms.
Eat this instead: U.S. wild-caught shrimp, particularly those from the Gulf of Mexico or pink shrimp from Oregon under Marine Stewardship Council guidelines.
Atlantic Flatfish (Flounder, Sole, Halibut)
Why it’s bad: This group of bottom-dwelling fish has faced severe population crashes due to industrial fishing since the 1800s. Stocks are estimated to be at just 1% of levels considered sustainable. In addition, Atlantic flatfish accumulate more pollutants from sediment and are susceptible to mislabeling.
- Includes flounder, sole, and Atlantic halibut from east coast fisheries.
Eat this instead: Pacific halibut (well-managed and more sustainable) or domestically farmed catfish and tilapia.
Atlantic Salmon (Both Wild-Caught and Farmed)
Why it’s bad: Wild Atlantic salmon is so endangered that commercial fishing is illegal. Most Atlantic salmon on the market is farmed, with environmental and health concerns. Salmon farms crowd thousands of fish into nets, encouraging disease, parasites, and the use of antibiotics and pesticides. Escaped farmed fish outcompete and interbreed with wild salmon, weakening populations and native biodiversity.
- Farmed salmon may contain higher levels of PCBs and dioxins than their wild Pacific counterparts.
Eat this instead: Wild-caught Pacific salmon, especially from Alaska, where fisheries are better managed.
Imported King Crab
Why it’s bad: The majority of king crab in American supermarkets is imported from Russia, where unsustainable fishing methods prevail. These practices damage habitats and often ignore regulations set to protect wild stocks.
- Russian king crab may be labeled generically as “red king crab,” making origins hard to trace.
Eat this instead: U.S.-caught king crab, sourced from Alaska, is better regulated for both environmental and health reasons.
Shark
Why it’s bad: Shark meat may be marketed under exotic names in gourmet settings, but sharks are top-of-the-food-chain predators that accumulate especially high levels of mercury and other toxins. Globally, shark populations have plummeted because of overfishing for their fins and meat, destabilizing marine ecosystems.
- Many shark species are now threatened or endangered.
Eat this instead: Sablefish (black cod) or U.S.-caught halibut. Both have milder ecologic and toxicological impacts.
Orange Roughy
Why it’s bad: Sometimes called “deep sea perch,” this fish lives up to 150 years, making it exceptionally slow to reproduce. Overfishing has decimated stocks, and their longevity means they accumulate more mercury and toxins over their lifetimes.
- Orange roughy is often found mislabeled, making it difficult for consumers to avoid.
Eat this instead: U.S.-sourced yellow snapper, yellow perch, or domestic farmed rainbow trout.
Chilean Sea Bass (Patagonian Toothfish)
Why it’s bad: Popular in high-end restaurants, Chilean sea bass is severely overfished and slow to mature. Its high mercury content poses health risks, especially to children and pregnant women. Many stocks are from illegal or unregulated fisheries in international waters.
- Can be labeled as “Patagonian toothfish” in some markets.
Eat this instead: U.S.-harvested Pacific sablefish or black cod.
Tilefish (Southern Atlantic)
Why it’s bad: Tilefish has consistently ranked among the highest in mercury contamination, prompting the FDA to advise high-risk populations (pregnant women and children) to avoid it. Fisheries for tilefish in the Gulf of Mexico are poorly regulated, exacerbating the risks of overharvesting and environmental harm.
Eat this instead: U.S. wild-caught Atlantic mackerel (low in mercury and sustainable).
Better Seafood Choices
Choosing wisely protects your health and helps restore ocean ecosystems. Consider these safer, more sustainable options:
- Wild-caught Pacific salmon (especially from Alaska)
- Domestic, farmed rainbow trout
- U.S. wild-caught Pacific halibut
- U.S. wild-caught shrimp and crab
- Atlantic mackerel (not king or Spanish varieties)
- Pacific sardines and anchovies
Always look for country of origin labeling and third-party certifications such as the Marine Stewardship Council (MSC) or Best Aquaculture Practices (BAP).
Fish to Completely Avoid: Quick Reference Table
| Fish | Primary Concern | Better Alternative |
|---|---|---|
| Imported Catfish | Chemical contaminants, poor regulation | U.S.-farmed catfish |
| Caviar (Beluga, Sturgeon) | Endangered, pollution | American Hackleback or Lake Sturgeon caviar |
| Atlantic Cod | Overfishing, ecological damage | Pacific cod |
| American Eel | PCBs, mercury, overfishing | Squid (calamari) |
| Imported Shrimp | Antibiotics, filth, habitat loss | U.S. wild-caught shrimp |
| Atlantic Flatfish | Overfishing, high contamination | Pacific halibut, farmed catfish |
| Atlantic Salmon (farmed/wild) | Pesticides, illegal harvest, pollution | Wild Pacific salmon |
| Imported King Crab | Illegal fishing habitat damage | U.S.-caught king crab |
| Shark | Mercury, population collapse | Sablefish, halibut |
| Orange Roughy | High mercury, slow reproduction | Yellow snapper or perch |
| Chilean Sea Bass | Overfishing, high mercury | Pacific black cod (sablefish) |
| Tilefish (Southern Atlantic) | Very high mercury | Atlantic mackerel |
What others are reading
Frequently Asked Questions (FAQs)
Q: Why is imported seafood often riskier than domestic?
A: Imported seafood may come from countries with weaker regulations on contaminants and antibiotics. In the U.S., less than 2% of imported seafood is inspected before reaching consumers, so dangerous substances may go unnoticed.
Q: Can cooking or freezing fish eliminate contaminants?
A: Cooking or freezing seafood kills most harmful bacteria but does not remove chemical pollutants like mercury or PCBs. These toxins are integrated into fish tissues and cannot be cooked away.
Q: What are the main health risks from eating high-mercury fish?
A: Mercury exposure in adults can harm the nervous, digestive, and immune systems. For pregnant women and children, it can impair brain development, causing lifelong learning issues. High-risk fish should be strictly limited, especially for vulnerable groups.
Q: How can I make more sustainable seafood choices?
A: Prioritize seafood caught or farmed in the U.S., look for Marine Stewardship Council (MSC) or Aquaculture Stewardship Council (ASC) certifications, and consult reputable guides like the Monterey Bay Aquarium’s Seafood Watch. Ask your fishmonger detailed questions about origin and catch methods.
Q: Are farmed fish safer or riskier than wild-caught?
A: Depends on the species and country of origin. U.S.-farmed fish like catfish and rainbow trout are usually well regulated, but imported farmed fish may contain more contaminants and antibiotics. Wild-caught Pacific salmon and halibut are generally considered sustainable and low in pollutants.
Key Takeaways for Healthy Seafood Eating
- Avoid fish with high mercury, industrial contaminants, or those facing overfishing crises.
- Choose U.S.-caught or sustainably certified seafood whenever possible.
- Mix up your choices to ease pressure on any single species—and diversify the nutrients you get.
By staying informed about the environmental and health risks of certain fish, you can make better choices for yourself and for future generations who depend on healthy oceans.
References
- https://draxe.com/nutrition/fish-you-should-never-eat/
- https://www.prevention.com/food-nutrition/healthy-eating/a20444313/12-unhealthy-fish-to-avoid-eating/
- https://www.goodhousekeeping.com/health/diet-nutrition/a20705842/fish-you-should-never-eat/
- https://www.webmd.com/diet/ss/slideshow-best-worst-fish
- https://doh.wa.gov/community-and-environment/food/fish/healthy-fish-guide
- https://www.healthvermont.gov/sites/default/files/document/env-rw-eat-fish-choose-wisely.pdf
- https://oehha.ca.gov/fish/general-health-advice-people-catching-and-eating-sport-fish-california
- https://www.nhs.uk/live-well/eat-well/food-types/fish-and-shellfish-nutrition/
Similar Articles
Read full bio of Sneha Tete
