What Fish Are Low in Mercury? A Complete List

Fish that are consistently low in mercury include salmon, sardines, anchovies, herring, shrimp, pollock, tilapia, catfish, scallops, and canned light tuna. These species share a common thread: they are small, they feed low on the food chain, or they grow quickly, all of which limit how much mercury accumulates in their flesh. But the spread between the safest and riskiest choices is enormous, and where a fish was caught, whether it was farmed, and even how you prepare it can shift the numbers.

The Low-Mercury List, Grouped by Category

Most regulatory agencies sort commercial fish into tiers based on average mercury concentration. While exact cutoffs vary by country, the groupings below reflect the broad scientific consensus from large surveys of commercial seafood.

Lowest mercury (generally under 0.1 ppm on average):

Low mercury (roughly 0.1–0.2 ppm on average):

For comparison, the fish you should limit or avoid entirely for mercury reasons sit at the opposite end: swordfish, shark, king mackerel, tilefish from the Gulf of Mexico, bigeye tuna, and marlin routinely exceed 0.5 ppm and can reach well above 1.0 ppm.

Why These Fish Stay Low

Mercury enters waterways mainly as inorganic mercury from industrial emissions, volcanic activity, and coal burning. Bacteria in sediment convert it to methylmercury, the organic form that accumulates in living tissue. From there, the process is straightforward: each step up the food chain concentrates mercury further. A study of an estuarine food web confirmed that mercury levels climbed with trophic level, with the organic form showing the strongest increase.6PubMed. Mercury biomagnification in a contaminated estuary food web: effects of age and trophic position using stable isotope analyses

This is why the low-mercury list is dominated by small, fast-growing, plankton-eating species. A sardine lives two to three years, eats plankton, and never gets the chance to accumulate much mercury. A swordfish lives over a decade, eats other fish that eat other fish, and concentrates mercury at every link. Size and lifespan matter too: within the same species, bigger and older individuals carry more mercury. Research on freshwater fish showed a clear positive relationship between fish length and total mercury concentration across multiple species.7PubMed Central. Mercury Levels in Freshwater Fish: Estimating Concentration with Fish Length to Determine Exposures Through Fish Consumption

Canned Tuna Deserves Its Own Conversation

Tuna is the most commonly eaten fish in many countries, and the mercury question lands differently depending on which can you grab. Canned light tuna, which is mostly skipjack, averaged about 0.12 ppm in one large analysis, while canned white (albacore) tuna averaged about 0.41 ppm.5PubMed. Mercury in canned tuna: white versus light and temporal variation That is more than a threefold difference. The reason is simple: albacore is a larger, longer-lived species than skipjack, so it accumulates more mercury over its lifetime.

A separate study measuring mercury residues in canned products found similar patterns. Canned salmon averaged about 45 parts per billion and canned mackerel about 55 ppb, both lower than even light tuna.8Journal of Food Science. Mercury and Fatty Acids in Canned Tuna, Salmon, and Mackerel If you eat canned fish regularly, swapping albacore for salmon or skipjack is one of the simplest ways to cut your mercury exposure without giving up the convenience or the omega-3s.

Farmed Fish Versus Wild-Caught

People sometimes assume wild fish are “cleaner” across the board, but for mercury, the opposite is generally true. A large quantitative synthesis of mercury data in commercial seafood found that farmed fish generally had lower mercury concentrations than their wild counterparts, with wild seafood showing two- to twelve-fold higher concentrations depending on the species.3PubMed Central. A Quantitative Synthesis of Mercury in Commercial Seafood and Implications for Exposure in the United States Farmed catfish, for example, had a maximum mean mercury concentration of just 0.030 ppm compared to 0.714 ppm for wild catfish in the same analysis.

The explanation is partly about diet control. Farmed fish eat manufactured feed pellets whose ingredients can be screened for contaminants, while wild fish eat whatever their ecosystem provides. Aquaculture researchers have even begun experimenting with selenium-enriched feeds made from tuna processing byproducts. One trial on farmed rainbow trout found that a tuna byproduct diet resulted in muscle mercury levels below the European Commission’s safety threshold, with specific selenium compounds in the feed reducing mercury bioaccumulation.9PubMed. Assessment of dietary Selenium and its role in Mercury fate in cultured fish rainbow trout with two sustainable aquafeeds

This does not mean all farmed fish are low in mercury or that farming eliminates the issue. It means that choosing farmed salmon or farmed tilapia over their wild equivalents tends to be a lower-mercury option, all else being equal.

The Omega-3 Tradeoff

The whole point of eating fish is the nutritional benefit, especially the long-chain omega-3 fatty acids EPA and DHA that are hard to get elsewhere. The trick is choosing fish where the omega-3 payoff is high and the mercury cost is low. Salmon and shrimp are principal sources of omega-3s while being lesser sources of methylmercury. Tuna provides omega-3s too, but with considerably higher mercury levels.2PubMed. Methylmercury and omega-3 fatty acids: co-occurrence of dietary sources with emphasis on fish and shellfish

A study in the New England Journal of Medicine illustrated why this balance matters for heart health specifically. Researchers found that mercury levels were directly associated with increased risk of heart attack, while DHA levels were associated with reduced risk, suggesting that mercury in fish may counteract some of the cardioprotective benefit of fish oils.10PubMed. Mercury, fish oils, and the risk of myocardial infarction In other words, not all fish meals are created equal. A serving of salmon delivers a high dose of protective fats with minimal mercury. A serving of swordfish delivers omega-3s too, but with enough mercury to potentially offset some of that benefit.

Risk-benefit analyses comparing multiple fish species have generally concluded that the benefits of normal fish consumption on outcomes like offspring IQ largely outweigh the risks from methylmercury, at least for commonly consumed species.11PubMed. Mercury, methylmercury and long-chain polyunsaturated fatty acids in selected fish species and comparison of approaches to risk-benefit analysis The message is not to stop eating fish. It is to eat the right fish.

Mercury and Pregnancy

Pregnant women hear the most about fish mercury, and for good reason. An overview of systematic reviews found that higher mercury exposure during pregnancy may be associated with higher risk of birth defects, preterm birth, low birth weight, and neurodevelopmental concerns in children including ADHD and autism spectrum disorder.12PubMed. Mercury exposure and childhood outcomes: An overview of systematic reviews But the picture is not simply “fish equals danger.” A US cohort study found that higher fish intake during pregnancy was associated with better cognitive test performance in children at age three, while higher mercury levels were associated with poorer scores. When the analysis accounted for both fish intake and mercury together, the opposing effects became even clearer: eating more than two servings per week was linked to meaningful cognitive gains, but being in the top tenth of mercury exposure wiped out part of that advantage.13American Journal of Epidemiology. Maternal Fish Intake during Pregnancy, Blood Mercury Levels, and Child Cognition at Age 3 Years in a US Cohort

This is exactly why the low-mercury species list matters most for women who are pregnant or planning to be. The goal is to keep eating fish for the omega-3 and protein benefits while choosing species where mercury exposure stays minimal. Sardines, salmon, shrimp, pollock, and canned light tuna are all good options. The species to avoid during pregnancy are the high-mercury predators: shark, swordfish, king mackerel, tilefish, and bigeye tuna.

Selenium as a Natural Counterweight

Mercury’s toxicity works in part by binding to selenium, an essential trace element your body needs to make certain protective enzymes. When mercury ties up selenium, it disrupts the production of those enzymes. The flip side is that selenium can also bind to mercury and reduce its biological availability, essentially sequestering it into inert compounds.14PubMed. Mercury: selenium interactions and health implications

This means the ratio of selenium to mercury in a fish may matter as much as the total mercury level. An emerging consensus in the research suggests that people consuming large amounts of fish with a selenium-to-mercury ratio below 1 are at higher risk from mercury toxicity, while a higher ratio may lower risk.15PubMed Central. Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: variation within species and relevance to risk communication Most ocean fish have ratios well above 1, meaning they contain far more selenium than mercury. The exceptions tend to be the same high-mercury predators that top every “avoid” list: certain sharks, pilot whale, and some large tuna species. For the low-mercury fish discussed in this article, the selenium-to-mercury ratio is not a concern because selenium naturally exceeds mercury by a wide margin.

Researchers have even reviewed the broader interactions between selenium status and dietary mercury exposure in at-risk populations, noting a protective effect of adequate selenium in people who eat a lot of fish.16PubMed Central. Selenium Status: Its Interactions with Dietary Mercury Exposure and Implications in Human Health None of this means selenium supplements are a mercury antidote, but it does suggest that the overall composition of a fish, not just its mercury number, shapes the real-world risk.

Does Cooking Change Mercury Levels?

People reasonably wonder if cooking can reduce mercury the way it kills bacteria. The answer is complicated and somewhat disappointing. While cooking does not reliably lower the total amount of mercury in a piece of fish, it can change how much of that mercury your body actually absorbs, a measurement researchers call bioaccessibility.

One study found that boiling and frying reduced mercury bioaccessibility by about 40% and 60%, respectively, compared to raw fish.17Environmental Research. Effects of various cooking methods and food components on bioaccessibility of mercury from fish A more recent study on pontic shad confirmed that baking and frying reduced mercury bioaccessibility compared to raw fish.18PubMed Central. Effects of cooking methods and co-ingested foods on mercury bioaccessibility in pontic shad (Alosa immaculata) However, a study specifically on sardines and sprats found no consistent reduction in total mercury or methylmercury from common cooking methods. In sardines, cooked samples actually showed higher dry-weight mercury concentrations than the raw sample, likely because cooking drove off water and concentrated what remained.19PubMed Central. Effects of Common Cooking Methods on Total Mercury and Methylmercury in Sardines and Sprats

The practical takeaway: cooking your fish is a good idea for food safety and may modestly reduce how much mercury you absorb, but it is not a reliable strategy for making a high-mercury fish safe. Species selection still matters far more than preparation method.

Where a Fish Was Caught Matters

Mercury contamination is not distributed evenly across the world’s waters. Industrial activity, coal-fired power plants, mining operations, and even natural geology create hotspots where fish carry more mercury than the same species caught elsewhere. A study of 19 saltwater species along the New Jersey coast found significant geographic variation in mercury levels for most species tested, with fish from northern New Jersey generally carrying less mercury than those from other regions.20PubMed Central. Locational differences in mercury and selenium levels in 19 species of saltwater fish from New Jersey The locational differences were greatest for species that already had the highest mercury concentrations, like shark, tuna, and bluefish.

Differences in methylmercury concentration between regions like China and the United States have prompted calls for better understanding of region-specific factors that drive mercury formation and biological uptake.21PubMed Central. Regional variation in fish mercury For the average consumer buying fish at a supermarket, this is hard to act on since labeling rarely specifies the exact catch location with enough detail to be useful. But for recreational anglers, it is highly relevant: your state fish advisory exists for a reason, and two lakes an hour apart can have very different contamination levels.

Recreational Anglers Face Different Risks

If you catch your own fish, the standard commercial-fish mercury guidance may not fully apply to you. In the general US population, saltwater fish from stores and restaurants account for most dietary methylmercury exposure. But for recreational and subsistence anglers, the picture flips. A study of Louisiana recreational anglers found that roughly 64% of participants’ fish meals and 74% of their estimated mercury intake came from recreationally caught seafood rather than commercial sources.22Environmental Health Perspectives. Fish Consumption and Mercury Exposure among Louisiana Recreational Anglers

A separate longitudinal study of freshwater anglers in the south-central United States found that freshwater species contributed 69% of fish consumption and 60% of dietary mercury exposure among participants, despite relatively low mercury concentrations in local fish.23PubMed Central. A longitudinal study of mercury exposure associated with consumption of freshwater fish from a reservoir in rural south central USA Volume mattered more than concentration: these anglers ate enough locally caught fish that even modest mercury levels added up. If you fish recreationally and eat your catch regularly, check your state’s fish consumption advisories for the specific water bodies you fish. Many states publish species-specific and lake-specific guidance that is far more useful than a generic “eat low-mercury fish” list.

Consumer Awareness Remains Surprisingly Low

Despite decades of public health messaging, awareness of mercury in fish stays stubbornly low across many populations. A large European survey covering 38 fish species found that while fish consumption increased between survey periods across all countries and species categories, awareness of chemical contaminants in fish remained generally low. Mercury was the most recognized contaminant, but that is a relative distinction in a landscape of overall poor awareness.24PubMed Central. Frequency of consumption of different fish, crustacean and mollusc species contributing to methylmercury exposure and consumer awareness of national advice on their consumption The survey also noted that consumption increased regardless of whether updated dietary advice had been issued, suggesting that guidance documents alone do not change behavior much.

This gap between available knowledge and actual behavior means that simple, memorable rules tend to matter more than detailed advisories. The most useful shorthand: eat small fish, eat fish that eat plants or plankton, and save the large predators for occasional treats rather than weekly staples. If you can remember that sardines, salmon, and shrimp are your best bets and that swordfish and shark are not, you have captured the vast majority of what the mercury science is trying to tell you.