Bluefin tuna tops the list, delivering about 50.8 grams of protein in a cooked 6-ounce fillet. That single serving covers your entire daily protein value. But several other fish come remarkably close, and depending on your budget, taste preferences, and health goals, a different species might be the better pick for you.
The 10 Highest-Protein Fish
These values are for cooked fillets, since that’s how you’ll actually eat them. Cooking concentrates protein by driving out water, so raw numbers will always look lower.
- Bluefin tuna (6 oz fillet): 50.8 g protein
- Grouper (1 fillet): 50.2 g
- Yellowfin tuna (6 oz fillet): 49.6 g
- Coho salmon, wild (6 oz fillet): 46.5 g
- Sockeye salmon (6 oz fillet): 45 g
- Snapper (1 fillet): 44.7 g
- Tilapia (6 oz fillet): 44.5 g
- Yellowtail (½ fillet): 43.3 g
- Wild Atlantic salmon (6 oz fillet): 43.2 g
- Northern pike (6 oz fillet): 42 g
The gap between the top and bottom of this list is only about 9 grams. In practical terms, any of these fish gives you a massive protein hit from a single serving.
Why Tuna Consistently Ranks First
Tuna is built for speed and endurance. Its muscle tissue is exceptionally dense, which translates directly into high protein per ounce. Bluefin and yellowfin are nearly identical in protein content, with bluefin edging ahead by about a gram per serving. Research comparing five commercial tuna species found no significant differences in average protein content between them. The white muscle tissue that makes up most of a tuna fillet runs between 20 and 24 percent protein by weight across all species tested.
The practical difference between tuna varieties comes down to fat and price, not protein. Bluefin carries more fat (which is why sushi-grade bluefin is so prized), while yellowfin and skipjack are leaner. Canned light tuna, typically skipjack, remains one of the cheapest high-protein foods at any grocery store.
Lean Fish vs. Fatty Fish for Protein
A common assumption is that lean white fish must have more protein because they have less fat. The reality is more nuanced. Lean fish like tilapia, cod, flounder, and sole stay under 120 calories per 3-ounce serving while still packing substantial protein. They’re excellent if you’re counting calories closely. But fattier fish like salmon and yellowtail aren’t far behind on protein, and they bring omega-3 fatty acids that lean fish lack.
Wild coho salmon, for example, sits at 46.5 grams of protein per 6-ounce fillet, higher than tilapia’s 44.5 grams. The extra calories from salmon come almost entirely from healthy fats. So if your only goal is grams of protein per calorie, lean white fish wins. If you want the best overall nutritional package, salmon and tuna give you protein plus heart-healthy fats in the same meal.
Grouper and Snapper: Underrated Options
Grouper deserves more attention. At 50.2 grams per fillet, it nearly matches bluefin tuna and is far more accessible at a typical seafood counter. It’s a firm, mild white fish that works with almost any preparation. Snapper, at 44.7 grams per fillet, is another strong choice with a slightly sweeter flavor profile.
Both fish are lean, versatile, and widely available fresh in coastal areas or frozen inland. If you find tuna too strong-tasting or too expensive for regular meals, grouper is the closest substitute in pure protein terms.
Mercury Matters at the Top of the List
The highest-protein fish aren’t always the safest to eat frequently. Larger predatory fish like bluefin tuna accumulate more mercury over their lifetimes, and that’s worth factoring into how often you eat them. FDA monitoring data paints a clear picture of which fish carry the least risk.
Tilapia averages just 0.013 parts per million of mercury, making it one of the cleanest options on the protein list. Fresh or frozen salmon comes in at 0.022 ppm. Both are low enough to eat multiple times per week without concern. Sardines (0.013 ppm), pollock (0.031 ppm), and catfish (0.024 ppm) are also excellent low-mercury choices, though they didn’t crack the top 10 for protein per serving.
For most people, rotating between tuna (once or twice a week) and lower-mercury fish like salmon and tilapia (as often as you like) gives you the best balance of high protein and low contaminant exposure. Pregnant women and young children typically benefit from sticking to the low-mercury options more strictly.
How Cooking Changes the Numbers
You’ll sometimes see raw protein values quoted online that look lower than the numbers above. That’s not an error. When fish is cooked, water evaporates and the protein becomes more concentrated per gram of flesh. Frying, baking, and smoking all increase measured protein density compared to the raw fillet. This is why it matters to compare cooked-to-cooked values, which is what the rankings above reflect.
The cooking method doesn’t add protein, of course. It just removes water weight. A 6-ounce raw fillet will weigh less after cooking, but the protein that was always there now makes up a larger share of what’s left. Grilling and baking preserve protein well without adding extra calories from oil. If you bread and deep-fry a fillet, you’re adding carbs and fat to a food that was naturally almost pure protein.
Best Budget Options for Protein Per Dollar
Bluefin tuna may lead the protein charts, but it can cost $20 or more per pound fresh. For everyday eating, tilapia and canned tuna are far more practical. Tilapia fillets typically run $3 to $5 per pound, and a 6-ounce serving still gives you 44.5 grams of protein. That’s roughly 10 grams of protein per dollar, which competes with chicken breast.
Canned salmon is another strong play. It’s shelf-stable, inexpensive, and retains the omega-3 benefits of fresh salmon with very low mercury levels (0.014 ppm for canned). A single can often contains 30 to 40 grams of protein for under $3. Northern pike, while harder to find in stores, is common for freshwater anglers and delivers 42 grams per 6-ounce fillet at no cost beyond a fishing license.
The best high-protein fish is ultimately the one you’ll eat consistently. Bluefin tuna wins on paper, but a rotation of tilapia, salmon, and canned tuna two to three times per week will deliver more total protein over time than an occasional splurge on premium cuts.