Salmon is the better choice for overall nutrition, primarily because it delivers dramatically more omega-3 fatty acids and vitamin D while carrying far less mercury. That said, tuna has real advantages if you’re watching calories or trying to maximize protein, and it costs less at the grocery store. The “better” fish depends on what your body needs most right now.
Calories, Protein, and Fat
Tuna is the leaner fish by a wide margin. Per 100 grams, bluefin tuna provides 144 calories, 23 grams of protein, and just 5 grams of fat. The same amount of Atlantic salmon comes in at 197 calories, 20 grams of protein, and 13 grams of fat. Yellowfin tuna is even leaner, with under 1 gram of fat per 3-ounce serving.
If your primary goal is high protein with minimal calories, tuna wins. It gives you about 15% more protein per calorie than salmon does. For anyone tracking macros on a cut or simply trying to keep meals light, canned light tuna in water is one of the most protein-dense foods you can buy.
Salmon’s higher fat content isn’t a downside, though. Most of that fat comes from omega-3 fatty acids, which is exactly the kind of fat most people don’t get enough of.
Omega-3s: Salmon’s Biggest Advantage
This is where the gap between the two fish becomes enormous. A 3-ounce serving of canned pink salmon delivers about 630 mg of DHA and 280 mg of EPA, the two omega-3 fats linked to heart and brain health. Wild Atlantic salmon provides around 350 mg of DHA per serving, and farmed Atlantic salmon about 590 mg.
Canned light tuna? Just 20 mg of DHA in the same portion. Yellowfin tuna drops to 10 mg. That means salmon can deliver 30 to 60 times more of these essential fats than common tuna varieties.
Omega-3s help lower triglycerides, slightly reduce blood pressure, and appear to lower the risk of heart disease, particularly sudden cardiac death. The Mayo Clinic notes that fatty fish like salmon provide the most omega-3s and “seem to help the heart the most.” If heart health is your motivation for eating fish, salmon is the clear winner.
Vitamins and Minerals
Salmon is one of the richest natural food sources of vitamin D. A 3-ounce serving provides roughly 375 IU, which covers about half the daily recommended intake for most adults. The same serving of tuna delivers only 40 IU. For people living in northern climates or spending most of their time indoors, this difference alone can make salmon the smarter pick.
Tuna holds its own in other areas. A 3-ounce portion supplies about 60 mcg of selenium (more than your full daily need) and 2 mcg of vitamin B12. Both fish are excellent sources of B vitamins and minerals overall, but salmon’s vitamin D content gives it a meaningful edge that’s hard to replicate from other foods.
Mercury Levels
Mercury is the main safety concern with any fish, and here the two aren’t even close. According to FDA monitoring data, fresh or frozen salmon averages just 0.022 parts per million (ppm) of mercury. Canned salmon is similarly low at 0.014 ppm.
Tuna varies widely by type. Canned light tuna (usually skipjack) averages 0.126 ppm, roughly six times higher than salmon but still considered low. Canned albacore jumps to 0.350 ppm, about 16 times the level in salmon. Fresh tuna steaks from larger species like bluefin or bigeye can be higher still.
For most adults eating fish twice a week, even albacore tuna falls within safe limits. But the difference matters for pregnant women and young children. The EPA and FDA classify salmon as a “Best Choice” fish, meaning pregnant or breastfeeding women can safely eat 2 to 3 servings per week. The agencies specifically recommend that children stick to “Best Choice” fish that are lowest in mercury, and salmon fits that category. If you’re feeding fish to kids regularly, salmon is the safer option.
Which Is Better for Weight Loss?
Tuna has a slight edge for pure calorie control. You can eat a full can of light tuna for under 100 calories while still getting around 20 grams of protein. That kind of calorie-to-protein ratio is hard to beat from any whole food source. For meal prepping or adding protein to salads without much caloric impact, tuna is the more practical choice.
Salmon’s higher calorie count comes with tradeoffs that may actually support weight management in a different way. Its fat content makes it more satiating per serving, and the omega-3s have anti-inflammatory properties that some research links to improved metabolic health. If you’re eating two servings of fish a week (as most guidelines suggest), the calorie difference between salmon and tuna adds up to only about 150 calories total. That’s a rounding error in a weekly diet.
Wild, Farmed, and Canned: Type Matters
Not all salmon or tuna is nutritionally equal. Wild coho salmon runs about 124 calories and 5 grams of fat per 3-ounce raw serving. Farmed Atlantic salmon is richer at 177 calories and 11 grams of fat, but also delivers more omega-3s. Both are good choices, though wild salmon tends to be leaner and lower in contaminants.
For tuna, the species you buy changes the nutrition and safety profile significantly. Skipjack (the most common canned light tuna) is lowest in mercury and calories. Albacore is fattier and contains more omega-3s than skipjack, but also carries nearly three times the mercury. Fresh yellowfin and bluefin steaks are excellent protein sources, but bluefin in particular raises sustainability concerns. All farmed bluefin tuna is rated red by Seafood Watch because it’s sourced from overexploited stocks.
Canned fish is often just as nutritious as fresh. Canned pink salmon retains its omega-3s and actually provides more DHA per serving than fresh wild salmon, partly because it includes the soft bones (also a good calcium source). Canned light tuna is affordable and convenient, though it can’t match salmon’s omega-3 content regardless of form.
Sustainability Considerations
If environmental impact factors into your choice, look at how the fish was caught. For tuna, labels that say “pole-caught,” “pole-and-line,” “troll-caught,” or “FAD-free” indicate more sustainable fishing methods. Avoid tuna caught with longlines or purse seines using fish aggregating devices (FADs), as these methods result in more bycatch and pressure on already stressed populations.
Albacore caught with trolling or pole-and-line methods earns Seafood Watch’s highest rating. Skipjack and yellowfin from the Maldives or labeled FAD-free are also solid choices. Wild-caught Alaskan salmon is generally considered one of the most sustainable seafood options available, though farmed salmon varies more depending on the operation.
The Bottom Line on Choosing Between Them
Salmon is the stronger all-around choice. It provides vastly more omega-3 fatty acids, nearly ten times the vitamin D, and carries a fraction of the mercury. For heart health, brain health, and overall nutrient density, it’s hard to argue against it. Tuna earns its place as a high-protein, low-calorie staple that’s budget-friendly and easy to keep on hand. The best approach for most people is eating both, leaning on salmon when you can and using tuna to fill in the gaps.