Most adults should eat two to three servings of fish per week, totaling at least 8 ounces. That’s the recommendation from the Dietary Guidelines for Americans, and the American Heart Association echoes it with a specific focus on fatty fish rich in omega-3s. A single serving is roughly the size of your palm, or about 4 ounces.
Why Two to Three Times a Week
The twice-a-week minimum isn’t arbitrary. It’s the amount consistently linked to lower risk of heart failure, coronary heart disease, stroke, and sudden cardiac death. The benefit comes primarily from omega-3 fatty acids (EPA and DHA), which your body can’t produce efficiently on its own. Two servings of fatty fish per week delivers a meaningful dose: a single 3-ounce portion of Atlantic salmon provides about 1.8 grams of combined EPA and DHA, while the same amount of sardines provides roughly 1.2 grams.
Not all fish deliver equal amounts of omega-3s. Salmon, herring, mackerel, and sardines are among the richest sources. Leaner fish like cod, tilapia, and shrimp still provide protein and other nutrients, but far less omega-3. A 3-ounce serving of shrimp contains only about 0.24 grams of EPA and DHA combined, compared to nearly eight times that in the same amount of salmon. If you’re eating fish primarily for heart benefits, choosing fattier species at least some of the time makes a real difference.
Which Fish to Choose
Mercury is the main reason some fish are better choices than others. Mercury accumulates in larger, longer-lived predatory species, and eating too much of those fish over time can cause problems ranging from memory issues and depression to numbness, muscle weakness, and difficulty with speech or vision.
Fish classified as “Best Choices” for low mercury include salmon (wild or farmed), sardines, anchovies, herring, Atlantic mackerel, cod, pollock, catfish, tilapia, shrimp, scallops, clams, and canned light tuna. You can safely eat two to three servings per week from this list.
“Good Choices” with moderate mercury levels include halibut, grouper, snapper, mahi mahi, lobster, canned albacore tuna, and yellowfin tuna. Limit these to one serving per week.
A handful of species should be avoided entirely due to high mercury: shark, swordfish, king mackerel, marlin, orange roughy, bigeye tuna, and tilefish from the Gulf of Mexico. Fresh or frozen tuna steaks of any variety also tend to run high in mercury, unlike canned light tuna.
Guidelines During Pregnancy and for Children
Pregnant and breastfeeding women should eat 8 to 12 ounces of low-mercury fish per week, sticking to the “Best Choices” list. That’s two to three servings of 4 ounces each. This range is higher than many people expect. The guidance isn’t to avoid fish during pregnancy but to eat it regularly while choosing species carefully. Developing brains are especially vulnerable to mercury, but they also benefit significantly from omega-3 fatty acids.
Children need fish too, but in smaller portions scaled to their age:
- Ages 1 to 3: about 1 ounce per serving
- Ages 4 to 7: about 2 ounces per serving
- Ages 8 to 10: about 3 ounces per serving
- Age 11 and up: about 4 ounces per serving
Children should eat two servings per week, chosen from the low-mercury “Best Choices” list.
Farmed vs. Wild Fish
Early studies raised concerns about higher PCB and contaminant levels in farmed salmon compared to wild-caught, but follow-up research hasn’t confirmed those findings. Stricter regulations on feed ingredients have lowered contaminant levels in farmed fish significantly. Both wild and farmed salmon now test low for mercury and PCBs. From a nutritional standpoint, the two are remarkably similar: a 3-ounce serving of farmed Atlantic salmon delivers about 1.83 grams of EPA and DHA, while wild Atlantic salmon provides about 1.57 grams. Either is a strong choice.
Can You Eat Too Much Fish?
If you’re sticking to low-mercury species, eating fish four or even five times a week is unlikely to cause problems. The mercury concern applies specifically to high-mercury fish eaten frequently over weeks and months. Mercury builds up in your body faster than you can clear it, and symptoms of excessive exposure, including a metallic taste in the mouth, tingling or numbness in the hands and feet, difficulty with coordination, and cognitive fog, can develop gradually enough that people don’t connect them to their diet.
The practical ceiling for most people isn’t really about fish itself. It’s about mercury exposure. Two to three servings of low-mercury fish per week is the sweet spot where you get the cardiovascular and nutritional benefits without meaningful mercury risk. If you want to eat fish more often, just keep varying your choices and favoring species from the low-mercury list.
Getting the Most From Your Servings
The omega-3 content varies dramatically across species, so what you eat matters as much as how often. If you’re eating fish twice a week and both servings are tilapia or shrimp, you’re getting very little omega-3. Swapping one of those meals for salmon, sardines, or herring changes the picture entirely. A simple pattern that works well: one serving of a fatty, omega-3-rich fish and one serving of whatever you enjoy, whether that’s shrimp, cod, or canned tuna.
Preparation matters too. Baking, broiling, and grilling preserve omega-3 content better than deep frying, which adds unhealthy fats and partially breaks down the beneficial ones. Canned fish like sardines and salmon are nutritionally comparable to fresh, often cheaper, and more convenient for weekday meals.
For those thinking about environmental impact, a 2025 Johns Hopkins study evaluating the ten most consumed seafood products in the U.S. found that sockeye salmon, frozen Alaska pollock, and canned tuna had the lowest environmental footprint in terms of energy use, freshwater consumption, and greenhouse gas emissions. All three happen to be solid nutritional choices as well.