When Should You Not Eat Fish for Safety and Health?

October 25, 2025 •

3 min read

According to the U.S. FDA, about 211 seafood companies were affected by recalls due to issues like bacterial contamination between 2015 and 2020 alone. Knowing when you should not eat fish is a crucial aspect of food safety, protecting you from common health risks such as mercury poisoning, bacterial infections, and allergic reactions.

Quick Summary

This guide covers the key circumstances under which consuming fish is not recommended, focusing on preventing foodborne illnesses and other health complications. Learn about the dangers of high mercury levels, seafood spoilage, specific allergies, and the importance of adhering to consumption advisories for vulnerable populations.

Key Points

Check for Spoilage: Never eat fish with a sour, rancid, or ammonia-like smell. Eyes should be clear and gills red.
Avoid During Pregnancy: Pregnant women, breastfeeding mothers, and young children should avoid high-mercury fish like shark, swordfish, and king mackerel.
Cook Thoroughly: Always cook fish to an internal temperature of 145°F (63°C) to kill bacteria and parasites, especially when pregnant or immunocompromised.
Beware of High Mercury: Limit or avoid large predatory fish due to high mercury levels. The EPA provides guidelines for safe consumption.
Heed Contamination Warnings: Check for local fish advisories from environmental agencies before eating wild-caught fish from rivers or bays.
Identify Allergies: If you experience hives, swelling, or digestive issues after eating fish, seek medical advice and avoid all fish products.
Stay Up-to-Date on Recalls: Regularly check official sources like the FDA for seafood recalls to avoid contaminated products.

Critical Health Conditions and Life Stages

Certain health conditions and life stages require heightened caution or complete avoidance of specific types of fish. For example, high levels of mercury in certain fish can pose a serious risk, especially to developing fetuses and young children. The mercury builds up over time and can cause neurological damage.

Pregnancy and Breastfeeding

For those who are pregnant, breastfeeding, or planning to become pregnant, avoiding large, predatory fish with high mercury levels is essential. These include shark, swordfish, king mackerel, and tilefish. Uncooked fish and shellfish should also be avoided due to the risk of bacterial and viral contamination, such as listeria, which can cause severe health complications for both the mother and baby. Cooked fish should reach an internal temperature of 145°F (63°C).

Young Children

Similar to pregnant women, young children are also particularly vulnerable to the effects of high mercury levels on their developing nervous systems. Health authorities recommend limiting or completely avoiding fish from the "Choices to Avoid" list for this age group.

Compromised Immune Systems

Individuals with weakened immune systems should be cautious with their seafood choices. Raw or undercooked fish, including sushi and sashimi, pose a higher risk of bacterial or parasitic infections. Thoroughly cooking fish is the safest preparation method for this group.

Signs of Spoiled Fish

Knowing how to identify spoiled fish is vital for preventing food poisoning. Trust your senses: look for visual cues and be mindful of the smell and texture. A rotten, sour, or overly "fishy" odor is a clear sign that the fish should be discarded.

Here are some warning signs of spoiled fish:

Smell: A fresh fish has a mild, ocean-like smell. A strong, sour, or ammonia-like odor is a major red flag.
Appearance: Fresh fish has clear, shiny eyes, while spoiled fish often has cloudy or milky eyes. The flesh should be firm, with no discoloration or dark spots.
Texture: If the fish feels slimy, has a sticky or milky film, or leaves an indentation when pressed, it is likely past its prime.

Fish with High Mercury and Contamination

Mercury is a neurotoxin that can accumulate in fish over time. Large predatory fish tend to have higher concentrations of mercury. Beyond mercury, certain waterways can be contaminated with PCBs, dioxins, and other pollutants, which can also bioaccumulate in fish.

Fish to avoid: Fish with the highest mercury levels include shark, swordfish, marlin, king mackerel, tilefish (Gulf of Mexico), and bigeye tuna.
Polluted waters: If you catch fish from local waters, check for local advisories regarding contamination levels. Ignoring these warnings can lead to the consumption of harmful toxins.

Comparison Table: Common Fish and Safety Considerations


Fish Type	Mercury Levels	Best for Vulnerable Groups?	Contamination Risk	Notes
Shark	High	No	High	Apex predator, should be avoided by all.
Salmon	Low	Yes, cooked	Low	Excellent source of Omega-3s. Cook thoroughly.
Swordfish	High	No	High	Limit or avoid due to high mercury.
Light Canned Tuna	Low	Yes, cooked	Low	Generally low in mercury, but limit intake.
Albacore Tuna	Medium	Limit	Medium	Higher mercury than light tuna, limit consumption.
Catfish	Low	Yes, cooked	Low	Generally safe and low in mercury.

Allergic Reactions

Fish allergies are one of the most common food allergies and can trigger severe, even life-threatening, reactions. Symptoms can include hives, abdominal pain, swelling, and in serious cases, anaphylaxis. If you have a known fish allergy, it is crucial to avoid all fish and seafood products, including cross-contamination.

Fish with Parasites

Raw or undercooked fish can harbor parasites. While many fish-specific parasites are harmless to humans, some can cause mild to moderate illness, and in rare cases, more serious health issues. Thoroughly cooking fish to a minimum internal temperature of 145°F (63°C) will kill any parasites, making the fish safe to eat. This is especially important for sushi-grade fish, which should still undergo proper freezing protocols to destroy parasites.

Conclusion: Making Informed Choices

While fish offers numerous health benefits, understanding the risks is key to safe consumption. You should not eat fish when it shows signs of spoilage, for certain individuals and life stages (like pregnancy) when consuming high-mercury varieties, and if you have a known allergy. Always opt for well-cooked seafood and consult local advisories, especially for wild-caught fish. By prioritizing safety, you can enjoy the nutritional advantages of fish while minimizing potential health hazards.

For additional guidance, consult the U.S. Food and Drug Administration (FDA) website for comprehensive seafood safety guidelines and recall information.

Frequently Asked Questions

You should only eat fish from local waterways if you have checked and adhered to local advisories. These warnings are issued by environmental agencies to inform the public about contamination risks, such as PCBs and mercury, that may be present in the water and accumulate in fish.

No, pregnant women should avoid all raw or undercooked fish and seafood, including sushi and sashimi. Raw seafood has a higher risk of containing harmful bacteria and parasites, such as listeria, which can cause severe health problems during pregnancy.

Signs of bad fish include cloudy or sunken eyes, gills that are not red, discolored or dull-looking flesh, and a slimy or milky film covering the surface. Fresh fish should have bright, clear eyes and firm, shiny skin.

The fish with the highest mercury content are large, predatory species, including shark, swordfish, king mackerel, tilefish from the Gulf of Mexico, and bigeye tuna. These should be limited or avoided, especially by pregnant women and young children.

Scombroid poisoning, caused by eating spoiled fish contaminated with high histamine levels, can cause symptoms like flushing of the face and neck, headaches, rash, sweating, and vomiting. These symptoms can resemble an allergic reaction and occur minutes to hours after consumption.

While proper handling and freezing can kill many parasites, raw fish always carries a higher risk of containing bacteria or parasites compared to cooked fish. Certain populations, such as pregnant women and those with compromised immune systems, should avoid raw fish entirely, even if labeled 'sushi-grade'.

If you have a fish allergy, you must avoid all fish and seafood. Even small amounts can trigger a reaction. Cross-contamination from shared utensils or cooking surfaces is also a risk. Symptoms can range from hives and swelling to life-threatening anaphylaxis.