A cooked fish fillet usually provides about 20 to 26 grams of protein per 3-ounce serving, though the species and portion size shift the total.
Fish fillet is one of the easiest ways to add lean protein to a meal without piling on heavy extras. That’s why this question comes up so often. You want a clear number, not a vague shrug. The catch is that fish fillet is not one single food. Cod, salmon, tilapia, haddock, halibut, tuna, and pollock all land in a slightly different spot, and the size of the fillet matters just as much as the species.
If you want the plain answer, most cooked fish fillets land in the low-20-gram range for a standard 3-ounce serving. A small fillet may sit closer to 17 to 20 grams. A thicker or larger fillet can climb well past 30 grams. Once you know that pattern, reading labels, building meals, and hitting a protein target gets a lot easier.
This article breaks down how much protein you can expect from common fish fillets, what changes the number, and how to estimate protein when the package gives serving sizes that don’t match what’s on your plate.
How Much Protein In Fish Fillet? By Type And Size
A standard reference point for fish nutrition is a cooked 3-ounce portion. That’s the size many nutrition charts use, and it gives a clean way to compare one fish against another. In that range, many fish fillets provide around 20 to 24 grams of protein. Lean white fish often sit near the lower end of that band. Denser fish can nudge higher.
That means a single average fillet can be a solid protein source even before you add sides. If your fillet weighs 5 to 6 ounces after cooking, you may be getting 30 grams or more. If it’s a small frozen portion, the total may be closer to 18 grams. The protein is still there. You just need to match the number to the portion in front of you.
Why protein numbers vary
Protein in fish fillet changes for three main reasons. The first is species. Tuna and salmon do not line up exactly with cod or catfish. The second is serving size. A thicker fillet simply contains more edible fish, so the protein total rises with it. The third is prep. Breaded or battered fish can lower the protein per ounce of finished weight because some of that weight comes from coating rather than fish.
Moisture loss during cooking can also make the number look a bit different. A cooked piece weighs less than a raw piece because some water cooks off. That does not mean the protein vanished. It just means the food became more concentrated.
What a fillet usually means on the plate
In home cooking, a fish fillet can range from a neat 3-ounce portion to a hearty restaurant piece that weighs 6, 7, or even 8 ounces after cooking. That gap is why one person says fish gives “about 20 grams” and another says “closer to 40 grams.” Both can be right. They are just picturing different portions.
A handy shortcut works well here: many cooked fish fillets provide roughly 7 to 8 grams of protein per ounce. That is not a label claim for every fish. It is just a practical estimate that gets you close for many common varieties.
Fish Fillet Protein Amounts In Common Varieties
The easiest way to make sense of fish fillet protein is to see the numbers side by side. The values below are based on cooked portions, which is how most people actually eat fish. These figures give you a strong ballpark for meal planning.
Common cooked fish protein range
Many popular fillets cluster tightly around the same protein range. That’s good news if you switch between white fish and oily fish during the week. You do not need to rebuild your whole meal plan every time you buy a different fillet. Most swaps stay pretty close.
According to the FDA seafood nutrition chart, a cooked 3-ounce portion of cod has about 20 grams of protein, haddock has 21 grams, halibut has 23 grams, salmon ranges around 22 to 24 grams depending on the type, tilapia has 22 grams, pollock has 20 grams, catfish has 17 grams, and tuna reaches about 26 grams.
| Fish fillet type | Protein in 3 oz cooked | What that means on the plate |
|---|---|---|
| Catfish | 17 g | A lighter protein pick for a smaller portion |
| Cod | 20 g | Lean, mild, and close to the standard fish average |
| Flounder or sole | 19 g | Thin fillets still give solid protein per serving |
| Haddock | 21 g | Good fit when you want white fish with a bit more protein |
| Halibut | 23 g | Dense fillets can push totals higher fast |
| Pollock | 20 g | Another lean choice that stays near the middle |
| Salmon | 22 to 24 g | Strong protein plus more fat than most white fish |
| Tilapia | 22 g | Consistent protein in an easy-to-cook fillet |
| Tuna | 26 g | One of the higher-protein cooked fish choices |
That table shows why fish works so well for protein-focused meals. Even the lower entries are still respectable. Once your portion gets larger than 3 ounces, the total rises in a straight line. A 6-ounce cooked cod fillet lands around 40 grams. A 6-ounce tuna steak can move into the low-50s.
How To Estimate Protein In A Full Fish Fillet
Labels and nutrition charts often use 3 ounces, but your actual fillet may not be anywhere near that size. So let’s turn the chart into something useful in the kitchen.
Use the ounce method
If a fish gives about 21 grams of protein in 3 ounces, divide 21 by 3. That gives 7 grams per ounce. From there, the math is easy:
- 4-ounce fillet: about 28 grams
- 5-ounce fillet: about 35 grams
- 6-ounce fillet: about 42 grams
- 7-ounce fillet: about 49 grams
This method is not perfect to the decimal, though it is close enough for everyday tracking. If you want more precision, weigh the cooked fillet and use the specific fish entry from the package or database.
Raw weight vs cooked weight
This trips people up all the time. If your package lists nutrition for raw fish and you weigh the fillet after cooking, the number will not match ounce for ounce. Fish loses water during cooking, so a cooked 4-ounce fillet may have started as a 5-ounce raw fillet. The protein stays in the fish while the water drops.
If you track macros closely, stick with one method every time. Either weigh raw and log raw, or weigh cooked and log cooked. Mixing the two throws off the count.
Fillet thickness changes the total more than people think
A long, thin sole fillet and a chunky salmon fillet may look similar on the plate from a distance. Once weighed, they often are not. Thick center cuts can carry far more protein than flatter tail pieces. That is one reason restaurant fish portions can vary so much even within the same order size on the menu.
The FDA advice about eating fish also points out that fish brings more than protein to the table, including nutrients such as vitamin B12, vitamin D, selenium, and, in many species, omega-3 fats. So protein matters, but it is not the whole story.
What Changes Protein In Breaded, Fried, And Frozen Fish Fillet
Not every fish fillet is a plain baked piece with lemon on top. Frozen breaded fillets, battered fish, and pan-fried portions can look similar, though their nutrition numbers can shift quite a bit.
Breaded fish often gives less protein per bite
When coating takes up more of the finished weight, the protein density falls. You are still eating fish, though part of the portion is flour, crumbs, starch, or batter. That means a 100-gram serving of breaded fish may contain less protein than 100 grams of plain baked fillet.
This does not make breaded fish a bad choice. It just means the number on the box matters more. Some frozen breaded fillets still provide a decent 12 to 18 grams per serving. Others land lower than that.
Frying does not erase protein
The cooking method changes fat and calories more than protein. A fried fish fillet still keeps most of the fish’s original protein. The bigger shift is that the coating and absorbed oil change the nutrition profile around it. If you only care about protein, fried fish still counts. If you care about the whole meal, you will want to look at calories, sodium, and fat too.
| Fish fillet style | Protein pattern | What to watch |
|---|---|---|
| Plain baked or grilled fillet | Usually highest protein density | Best for easy portion math |
| Pan-seared fillet | Protein stays close to plain fish | Oil changes calories more than protein |
| Breaded frozen fillet | Often lower protein per ounce | Check serving size and coating share |
| Battered fried fillet | Still decent protein, lower density | Calories and sodium can climb fast |
| Fish sandwich fillet | Protein depends on fish portion inside | Bun and sauce do not add much protein |
Best Fish Fillet Choices If You Want More Protein
If your goal is to squeeze more protein from the same plate space, denser fish and larger plain fillets usually win. Tuna sits near the top among common cooked choices. Halibut, salmon, tilapia, and haddock also perform well. Cod and pollock are not far behind, which is why they remain staples in meal prep plans.
White fish can feel lighter and still deliver a strong protein hit. Oily fish such as salmon may give a similar protein total with more fat, which can make the meal more filling. Neither route is wrong. It depends on what the rest of your day looks like.
Good picks for leaner meals
If you want a high-protein fillet with fewer calories, cod, pollock, haddock, tilapia, and flounder are easy places to start. They are mild, flexible, and simple to pair with rice, potatoes, vegetables, or salads.
Good picks for fuller meals
If you want protein plus richer texture, salmon and trout pull more weight. They still bring a strong protein total, though they also carry more fat than most white fish. That can be a plus if you want a meal that sticks with you longer.
Easy Ways To Count Protein In Your Meal
You do not need a lab to get this right. Three simple habits make fish fillet protein much easier to track.
Weigh the cooked portion
A small kitchen scale clears up most guesswork. Weigh the fish after cooking if that is how you log food. Then multiply the ounces by a rough protein estimate for that fish, or use the label entry if you have it.
Use package data when the brand gives it
Packaged frozen fillets often list nutrition for one fillet or one serving. That is better than guessing, especially when coating or added ingredients are involved.
Think in ranges, not perfect single numbers
If you are eating a plain cooked fish fillet and do not know the species, a rough estimate of 20 to 25 grams of protein for a standard serving is a smart place to start. That will put you in the right zone most of the time.
For a full dinner portion, many fish fillets end up delivering 30 grams or more. That is why fish works so well in lunches, weeknight dinners, and meal prep boxes. It is easy to cook, easy to portion, and easy to fit into a higher-protein eating pattern.
References & Sources
- U.S. Food and Drug Administration (FDA).“Nutrition Information for Cooked Seafood (Purchased Raw).”Provides protein values for common cooked seafood servings, including cod, salmon, haddock, halibut, tilapia, pollock, catfish, and tuna.
- U.S. Food and Drug Administration (FDA).“Advice about Eating Fish.”Explains that fish is part of a healthy eating pattern and supplies nutrients such as protein, vitamin B12, vitamin D, selenium, and omega-3 fats.
