Farm-Raised Fish to Avoid: Tilapia, Salmon & Hidden Risks

QUICK SUMMARY

Which farm-raised fish should you avoid? All of them: farmed salmon, tilapia, catfish, and trout. Farmed tilapia and catfish are low in omega-3s and high in omega-6s, and in the largest comparison of farmed and wild salmon, farmed fish carried significantly more PCBs, dioxins, toxaphene, and dieldrin, much of it from the fishmeal and fish oil they are fed. Choose wild-caught salmon, sardines, herring, anchovies, and other low-mercury wild fish instead.

Fish is supposed to be one of the healthy foods, right? Wild fish is. But walk through a grocery store and you will see packages labeled Atlantic salmon, tilapia, catfish, and trout with no explanation of how those fish were raised or what they were fed.

That matters to us. When we choose food for our family, we want to know what the animal ate, whether the source is trustworthy, and what kind of food system our purchase supports.

Our position is straightforward: avoid farm-raised fish and choose carefully sourced wild-caught seafood. That includes farmed salmon, even though salmon is famous for its omega-3 content. Here is what the research shows, and what we eat instead.

Unhealthy Tilapia vs Salmon Fish

In 2008, researchers at Wake Forest University tested 30 commonly eaten farmed and wild fish bought from supermarkets and wholesalers across the United States. Tilapia, the fastest-growing and most widely farmed fish, and catfish had much lower concentrations of omega-3s and very high ratios of long-chain omega-6 to omega-3 fats. (1)

In the words of the researchers, “marked changes in the fishing industry during the past decade have produced widely eaten fish that have fatty acid characteristics that are generally accepted to be inflammatory by the health care community.” (1)

You may have seen the headline that eating tilapia is worse than eating bacon. The study did not compare tilapia with bacon; it measured fats. What it found is reason enough to pass on tilapia.

Why the Omega-6 to Omega-3 Ratio Matters

A frequently cited review in Biomedicine & Pharmacotherapy put it this way: “human beings evolved on a diet with a ratio of omega-6 to omega-3 essential fatty acids (EFA) of approximately 1 whereas in Western diets the ratio is 15/1-16.7/1.” (2)

According to the same review, a very high omega-6 to omega-3 ratio promotes many diseases, while more omega-3 has the opposite effect. In heart patients, a ratio of 4 to 1 was associated with a 70 percent decrease in total mortality. (2) The diseases tied to a high ratio include:

• Autoimmune disease
• Cancer
• Cardiovascular disease
• Inflammatory disease

Most families already eat too little omega-3 and too much omega-6 from refined and processed foods. Fish that adds more omega-6 is working against you, so we choose better sources of omega-3 fatty acids.

Is Farmed Salmon Any Better?

Farmed salmon does contain omega-3s; the Wake Forest team found Atlantic salmon and trout relatively high in them. (1) So don’t think it is only tilapia. The problem with farmed salmon is what comes with those omega-3s.

Farm Raised Fish in Stores

Most salmon on the market today is farmed, and that matters for two reasons.

First, the fat is different. In a large 2005 comparison, researchers analyzed 459 farmed Atlantic salmon, 135 wild Pacific salmon, and 144 supermarket farmed fillets from 16 cities in North America and Europe. Wild salmon carried about ten times more omega-3 than omega-6, farmed salmon only three to four times, and farmed salmon averaged 16.6 percent fat against 6.4 percent in wild fish. (3)

Second, the contaminants are different. The same study found significantly higher levels of PCBs, dioxins, toxaphene, and dieldrin in farmed Atlantic salmon than in wild Pacific salmon. As the researchers concluded, “The presence of these contaminants may reduce the net health benefits derived from the consumption of farmed salmon.” (3)

What Farmed Fish Are Fed

Farmed fish eat a formulated feed, and the recipe changes with price and availability. Ingredients used in aquaculture feed include:

• Fish meal and fish oil
• Poultry meal or poultry fat
• Soybean meal and other plant proteins
• Wheat, corn, or other grains
• Rapeseed or other vegetable oils

The fish oil and fishmeal are where much of the contamination enters. Feed for farmed salmon is often made largely from ground-up small fish and designed to be high in fish oil, and PCBs concentrate in oils and fat. (4)

What About Crowding, Disease, and Antibiotics?

Crowding can increase the challenges of disease and parasites, depending on the species and production system. Some farms use veterinary medicines, vaccines, improved husbandry, or other interventions. Regulations and practices vary substantially by country.

We want to know whether a producer discloses how its fish are raised and treated. Most grocery labels tell you nothing, and that alone is reason to choose wild fish we can trace.

PCB Problems in Farm Raised Fish to Avoid

When the Environmental Working Group tested farmed salmon from grocery stores in Washington, DC, San Francisco, and Portland, Oregon, seven of ten fish “were contaminated with polychlorinated biphenyls (PCBs) at levels that raise health concerns.” (4)

On average, those farmed salmon had 16 times the dioxin-like PCBs found in wild salmon, 4 times the levels in beef, and 3.4 times the levels in other seafood. EWG concluded that farmed salmon are likely the most PCB-contaminated protein source in the U.S. food supply. (4)

PCBs, or polychlorinated biphenyls, are industrial chemicals once used in electrical equipment. Their manufacture was banned in the United States in 1979, but they break down slowly and remain in soils, sediments, and food webs for decades. (5)

They also build up as they move up the food chain. In Lake Michigan, PCB levels in coho and chinook salmon were roughly 20 to 30 times higher than in the small creatures two steps down the food chain. (6) Wild fish from polluted waters carry them too, which is why where a fish comes from matters as much as the word “wild.”

The EPA classifies PCBs as probable human carcinogens and describes several other effects. (5)

1. Immune System Effects

In monkeys and other animals, PCB exposure shrank the thymus, weakened immune responses, and lowered resistance to Epstein-Barr virus and other infections. In people, the EPA reports that Epstein-Barr infection combined with PCB exposure raised the risk of non-Hodgkin’s lymphoma. (5)

2. Reproductive and Developmental Effects

In animal studies, PCB exposure reduced birth weight, conception rates, and live birth rates, and it reduced sperm counts in rats. According to the EPA, “Effects in monkeys were long lasting and were observed long after the dosing with PCBs occurred.” (5)

3. Nervous System and Thyroid Effects

Newborn monkeys exposed to PCBs showed lasting deficits in visual recognition, short-term memory, and learning, and human studies suggest similar learning effects. PCBs also alter thyroid hormone levels in humans and animals. (5)

This is why we think about the whole pattern of what our family eats. You do not need to panic about a past meal. You do need a plan for choosing seafood every week.

What the FDA Says

The FDA’s position is that levels of contaminants other than mercury in commercial fish generally do not raise human health concerns. (9) The independent testing above says otherwise for farmed salmon, and our family chooses accordingly.

Other Contaminants of Farm Raised Fish

PCBs are not the only problem. The 2005 salmon study measured three more persistent pollutants, and all three were significantly higher in farmed fish. (3)

Dioxins

Dioxins are byproducts of industrial and combustion processes. They are persistent, accumulate in fatty tissue, and move up food chains, and farmed salmon carries more than twice the fat of wild salmon for them to settle in. (3)

Toxaphene

Toxaphene is a pesticide mixture whose use was discontinued in the United States decades ago. Because it persists in the environment, it still turns up in aquatic food webs.

Dieldrin

Dieldrin is another persistent pesticide that remains in soil and sediment long after use stops. Fish encounter it when their environment or feed is contaminated.

Mercury and Methylmercury

Mercury changes the way we shop for wild fish. In water it becomes methylmercury, which builds up in fish tissue, and larger, longer-lived predators carry the most.

The FDA/EPA advice lists king mackerel, marlin, orange roughy, shark, swordfish, Gulf of Mexico tilefish, and bigeye tuna as the highest-mercury choices to avoid. Salmon, sardines, anchovies, herring, and pollock are among the lower-mercury Best Choices. (8)

Mercury is found throughout the tissue of the fish, so trimming and cooking will not reduce it. Species and source are the tools that work. (9)

What About Microplastics?

Microplastics and other emerging contaminants are receiving growing research attention in aquatic environments. We reduce what we can control, and the source of our fish is one of those things.

Importance of Eating Wild Caught Fish

Avoiding farmed fish is only half the answer. The other half is what goes on the plate instead, and wild fish is one of the most nourishing foods God gave us.

According to USDA data, 100 grams of cooked wild sockeye salmon provides: (7)

• 26.5 grams of protein
• About 0.86 grams of the omega-3s EPA and DHA
• 4.47 micrograms of vitamin B12
• 670 IU of vitamin D
• 35.5 micrograms of selenium
• 10.1 milligrams of niacin and 0.83 milligrams of vitamin B6
• 305 milligrams of phosphorus and 113 milligrams of choline

Our Favorite Wild-Caught Alternatives

Wild salmon: Our go-to source of marine omega-3s. Look for a clearly identified species and origin; frozen or canned wild Alaskan salmon makes it more affordable.

Sardines: Small, low-mercury, and rich in EPA and DHA. Canned sardines make a quick meal.

Herring: Another oily fish full of marine omega-3s. Watch the salt in pickled or smoked versions.

Anchovies: Small and flavorful in salads, sauces, and dressings. Check sodium in preserved products.

Wild pollock: Mild and budget-friendly. It is leaner than salmon, so it gives you protein more than omega-3s.

Other wild fish: Wild trout, cod, and other species can fit your family’s meals. Always confirm the fish is wild-caught and check local advisories for fish from lakes and rivers.

How to Read Seafood Labels

Look for the species name, the country or region of origin, and the words wild-caught or farm-raised. A trustworthy seller can tell you where the fish came from.

Some “wild-caught” fish began life in a hatchery, and wild-caught does not automatically mean sustainably harvested. Our preference for wild seafood goes hand in hand with caring for the oceans and rivers God created.

If a seller cannot answer basic questions about origin and species, we walk away. There are other meals we can make that night.

How to Buy Better Fish on a Budget

One reason families buy farmed fish is cost. We understand that; feeding a household is expensive.

Start with frozen wild-caught fillets, which are convenient and nutritious. Compare price per pound, watch for sales on canned wild salmon and sardines, and rotate fish with other nourishing proteins. Canned wild salmon patties with roasted vegetables can feed a big family well.

If you’re looking for reliable suppliers, look for a meat supplier you can trust and ask about seafood sourcing, traceability, and handling.

Pregnancy and Children

Pregnancy is not the time to avoid all seafood. DHA, iodine, and choline from fish matter for a baby’s development, and the FDA/EPA advice recommends 8 to 12 ounces a week, two to three servings, from the lower-mercury Best Choices. (8)

Wild salmon and sardines fit that perfectly. Children need smaller portions by age, from the same low-mercury list.

Farm-Raised Fish FAQs

Which farm-raised fish should I avoid?

We avoid all farm-raised fish, including salmon, tilapia, catfish, and trout. Tilapia and catfish are low in omega-3s and high in omega-6s, and farmed salmon carries significantly more PCBs, dioxins, toxaphene, and dieldrin than wild salmon. (1, 3)

Is farm-raised salmon unhealthy?

Farmed salmon has omega-3s, but it also has far less favorable fat ratios and significantly higher levels of persistent pollutants than wild salmon. The researchers who measured it concluded those contaminants “may reduce the net health benefits” of eating it. (3)

Is tilapia worse than bacon?

No study compared them. The 2008 Wake Forest study found that farmed tilapia is low in omega-3s and very high in omega-6s, fats the researchers described as “generally accepted to be inflammatory.” (1)

Does wild-caught fish contain PCBs or mercury?

It can. Large predatory fish carry the most mercury, and fish from polluted lakes and rivers can carry PCBs, so choose low-mercury species and check local advisories.

Can pregnant women eat wild salmon?

Yes. Salmon is one of the FDA/EPA Best Choices, and wild salmon gives you the omega-3s without the farmed-fish contaminants. (8)

Our Bottom Line on Farm-Raised Fish

Know the source, choose low-mercury wild species, and leave farmed fish in the case. That is the standard we keep in our home.

We believe caring for our bodies is part of faithful stewardship. God has entrusted us with our lives, our families, and a remarkable creation, and we thank Him for the wild fish He provides.

Keep reading: What Does the Bible Say About Seafood? · Bioactive Foods: The Essential Eight · Why Is Processed Meat Bad for You?