Salmon is the healthier choice overall, mainly because it delivers far more omega-3 fatty acids and carries less mercury than halibut. That said, halibut has real advantages of its own: fewer calories, less fat, and a mild flavor that works for people who don’t love the taste of oilier fish. The “better” pick depends on what you’re optimizing for.
Calories, Protein, and Fat
In a 3-ounce cooked serving, halibut and salmon deliver nearly identical protein (about 22 grams each), but the similarity ends there. Broiled halibut comes in at roughly 120 calories with just 2 grams of total fat. Atlantic salmon lands around 150 calories with 7 grams of fat, and wild sockeye salmon runs even higher at 180 to 190 calories with about 9 grams of fat.
If you’re watching calories or total fat intake, halibut is the leaner option by a wide margin. But most of salmon’s extra fat comes from omega-3s, which are exactly the kind of fat most people need more of. So those extra calories aren’t empty; they’re doing real cardiovascular work.
Omega-3s: Salmon’s Biggest Advantage
This is where the gap between the two fish is hardest to ignore. A 3-ounce serving of farmed Atlantic salmon provides about 1,830 milligrams of EPA and DHA combined. Wild Atlantic salmon delivers around 1,570 milligrams. Greenland halibut, the fattiest variety of halibut, contains roughly 1,000 milligrams per serving. Standard Pacific halibut, which is what you’ll find in most grocery stores and restaurants, has considerably less: around 400 milligrams per serving.
EPA and DHA are the two omega-3 fats most strongly linked to heart health, reduced inflammation, and brain function. Most health organizations recommend at least 250 to 500 milligrams per day. A single serving of salmon covers that easily. With Pacific halibut, you’re getting a useful dose but not the concentrated hit that makes salmon one of the top omega-3 sources in the American diet.
Mercury: A Notable Difference
Halibut contains significantly more mercury than salmon. According to FDA testing data, halibut averages 0.241 parts per million of mercury, while fresh or frozen salmon averages just 0.022 ppm. That makes halibut roughly 11 times higher in mercury than salmon.
For most healthy adults eating fish a couple of times a week, halibut’s mercury level isn’t dangerous. The FDA categorizes it as a “Good Choice,” meaning it’s safe to eat once a week. Salmon earns the FDA’s top “Best Choice” rating, meaning you can safely eat two to three servings per week.
The distinction matters most for pregnant or breastfeeding people and young children. The FDA recommends these groups eat 8 to 12 ounces per week from the “Best Choices” list (which includes salmon) or limit themselves to one serving from the “Good Choices” list (which includes halibut). For a pregnant person, a serving is 4 ounces. For children, serving sizes scale with age: about 1 ounce for toddlers, 2 ounces for ages 4 to 7, and 3 to 4 ounces for older kids.
Minerals and Micronutrients
Both fish are good sources of B vitamins, selenium, and phosphorus. Salmon has a slight edge in potassium, with wild sockeye providing around 436 to 550 milligrams per 100 grams, and magnesium content ranging from 28 to 37 milligrams depending on the species. Halibut is also known as a solid magnesium source, though specific values vary by preparation.
Salmon, particularly wild varieties with reddish-pink flesh, also contains astaxanthin, a pigment that functions as an antioxidant. Halibut’s white flesh doesn’t provide this compound. Neither fish contains carbohydrates, making both suitable for low-carb eating patterns.
Which Is Better for Weight Loss?
If your primary goal is cutting calories while keeping protein high, halibut is the stronger choice. At 120 calories per serving with virtually no saturated fat, it fits easily into a calorie deficit. It falls into the same lean-fish category as cod, flounder, and tilapia, all of which clock in under 120 calories per 3-ounce serving while delivering substantial protein.
Salmon works for weight loss too, but you’re spending 25 to 50 percent more calories per serving. For most people, the extra 30 to 70 calories won’t make or break a diet. The omega-3s in salmon may also support metabolic health in ways that a simple calorie count doesn’t capture. If you’re eating fish twice a week as part of a balanced diet, the calorie difference between halibut and salmon is minor over the course of a week.
Which Is Better for Heart Health?
Salmon wins here. The concentration of omega-3 fatty acids in salmon is its defining nutritional advantage. EPA and DHA help lower triglycerides, reduce blood pressure, and decrease inflammation in blood vessels. These effects are dose-dependent, meaning higher intake generally produces greater benefit, and salmon simply delivers more per serving than halibut does.
That doesn’t mean halibut is bad for your heart. Any fish is better than no fish, and halibut still provides some omega-3s along with lean protein. But if you’re choosing between the two specifically for cardiovascular benefit, salmon is the clear pick.
Taste and Versatility
Halibut has a mild, slightly sweet flavor and a firm, dense texture that holds up well on the grill or in a pan sear. People who find salmon too “fishy” often prefer halibut. Its neutral taste also absorbs sauces and seasonings more readily.
Salmon has a richer, more distinctive flavor. Its higher fat content makes it more forgiving to cook (it stays moist even when slightly overdone) and gives it that buttery quality people either love or avoid. Salmon is also more widely available and typically less expensive than halibut, which can be a practical factor if you’re eating fish regularly.
The Bottom Line on Choosing Between Them
For overall nutritional impact, salmon is the stronger choice. Its omega-3 content is hard to match, its mercury levels are very low, and the FDA gives it the widest safety margin for frequent consumption. If heart health, brain health, or pregnancy nutrition is your priority, salmon is the better fish.
Halibut earns its place if you’re focused on keeping calories and fat low, if you prefer milder-tasting fish, or if you simply want variety in your seafood rotation. Eating both throughout the week is a perfectly reasonable approach, and either one puts you ahead of the roughly 80 percent of Americans who don’t eat enough seafood.