Bluefin tuna tops the list of high-protein fish, delivering about 30 grams of protein per 100 grams when cooked. Several other species come close, and the best choice for you depends on how you buy and prepare your fish, your budget, and how often you eat it.
The Highest-Protein Fish Species
When ranked by protein per 100 grams of cooked fish, the leaders are:
- Bluefin tuna: 29.9 g
- Yellowtail: 29.7 g
- Yellowfin tuna (ahi): 29.2 g
- Canned anchovies (oil-drained): 28.9 g
- Smoked sturgeon: 31.2 g
Smoked sturgeon technically ranks first, but that number reflects the smoking process, which removes a significant amount of water and concentrates the protein. Among fresh fish cooked with dry heat, bluefin tuna leads. Yellowfin tuna is worth highlighting because it’s far easier to find in grocery stores and restaurants than bluefin, and at 29.2 grams per 100-gram serving, the difference is negligible. Yellowfin is also nearly 70% water and contains just 0.6 grams of fat, making it one of the leanest protein sources in any food category.
How Common Fish Compare
Not everyone is shopping for tuna steaks. If you’re reaching for more affordable, everyday fish, the protein content is still impressive, just a few grams lower per serving.
Cooked tilapia provides about 26.2 grams of protein per 100 grams, which makes it one of the better values considering its low price. Cod comes in at 22.8 grams. Both are lean white fish with mild flavor, and they work well for people who don’t love the taste of stronger fish like tuna or anchovies.
Salmon, often praised for its omega-3 fats, falls in a similar range to tilapia for protein. The tradeoff is a higher fat content, which means slightly fewer grams of protein per bite but more of the fatty acids linked to heart and brain health. If pure protein density is your goal, tuna and tilapia beat salmon. If overall nutrition matters more, salmon holds its own.
Canned Tuna vs. Fresh Tuna
Canned tuna is one of the cheapest and most convenient protein sources available, so it’s worth knowing how it stacks up against fresh. The short answer: it’s close, but fresh has a slight edge.
In a 3-ounce serving, fresh yellowfin tuna provides about 21 grams of protein, while canned albacore (white tuna) packed in water delivers around 20 grams. Canned skipjack, the “light” tuna most people buy, drops to about 16 grams per serving. The heat used during canning breaks down some protein, which explains the gap. Even so, ounce for ounce, canned tuna provides as much protein as beef, chicken, or pork.
If you’re using canned tuna as a regular protein source, choosing albacore over light tuna gets you closer to fresh tuna’s numbers.
Why Cooked Fish Has More Protein per Bite
You’ll sometimes see different protein numbers for the same fish depending on whether the data is based on raw or cooked weight. This isn’t an error. Fish loses water during cooking, so the same piece of fish weighs less afterward while retaining nearly all its protein. A 4-ounce raw fillet that shrinks to about 3 ounces after grilling will have a higher protein concentration per gram in its cooked form. Expect roughly 30 to 35 grams of protein from a 4-ounce portion of cooked fish, depending on species.
This also means your cooking method matters. Grilling and baking drive off more moisture than poaching or steaming, so a grilled tuna steak will be slightly more protein-dense by weight than a poached one, even though the actual protein content of the original fillet is the same.
Mercury Levels in High-Protein Fish
The fish with the most protein tend to be larger, predatory species, and those accumulate more mercury. Fresh yellowfin tuna averages 0.354 parts per million of mercury. Canned albacore is similar at 0.350 ppm. These aren’t dangerous in moderate amounts, but they’re high enough that eating them daily could be a concern over time, particularly for pregnant women and young children.
For comparison, tilapia contains just 0.013 ppm and salmon 0.022 ppm, making them essentially negligible for mercury risk. Cod sits at 0.111 ppm, and halibut at 0.241 ppm. If you eat fish several times a week and want to keep mercury exposure low, rotating between high-protein tuna and lower-mercury options like tilapia or salmon is a practical approach. You still get plenty of protein from any of these fish. The difference between 26 grams and 30 grams per serving is real but small, and it’s unlikely to matter more than simply eating fish consistently.