A 100-gram serving of catfish (about 3.5 ounces) contains roughly 16 grams of protein and 118 calories. That makes catfish a solid, lean protein source where more than half the calories, around 54%, come directly from protein. The rest comes from fat, with zero carbohydrates.
Protein by Serving Size
Most people don’t weigh their fish on a kitchen scale, so here’s what the numbers look like in practical terms. A standard catfish fillet runs between 100 and 170 grams depending on the size of the fish, which puts you in the range of 16 to 28 grams of protein per fillet. A typical restaurant portion of two fillets can deliver 32 to 40 grams, covering a substantial chunk of most people’s daily protein needs.
For context, the protein in catfish stacks up reasonably well against other popular white fish, though it doesn’t top the list. Tilapia leads with about 29 to 30 grams of protein per serving, cod comes in around 19 to 20 grams, and catfish falls in the 16 to 19 gram range. The tradeoff is that catfish has a richer flavor and slightly higher fat content, which many people prefer for taste.
Protein Quality and Amino Acids
Catfish is a complete protein, meaning it supplies all nine essential amino acids your body can’t make on its own. It’s particularly rich in lysine and methionine, two amino acids that can be harder to get from plant-based diets. Lysine plays a key role in muscle repair and calcium absorption, while methionine supports metabolism and detoxification processes in the liver. If you’re relying on catfish as a primary protein source in your meals, you’re getting a well-rounded amino acid profile comparable to other animal proteins.
How Cooking Changes the Numbers
The way you cook catfish doesn’t significantly change its protein content, but it dramatically changes the calorie count. Research comparing deep-fried and oven-baked fish found no meaningful difference in protein between the two methods. The difference shows up in fat and calories: deep-fried fish nuggets came in around 247 calories per 100 grams, while oven-baked versions hit about 207 calories for the same amount.
That calorie gap happens because frying replaces water lost during cooking with oil. The fish absorbs fat from the fryer, nearly doubling its fat content compared to baking. So if you’re eating catfish for its protein-to-calorie ratio, baking, grilling, or broiling will keep that ratio favorable. A classic Southern-fried catfish dinner is delicious, but the breading and oil can easily push a fillet past 300 calories without adding any extra protein.
Other Nutrients Worth Knowing
Protein gets the headline, but catfish is quietly one of the better sources of vitamin B12 in the average diet. A single 3.5-ounce serving delivers 121% of the daily value for B12, a vitamin essential for nerve function and red blood cell production. The same serving provides 26% of your daily selenium, which supports thyroid health and acts as an antioxidant, along with 24% of your daily phosphorus for bone maintenance.
Catfish is also one of the lowest-mercury fish you can eat. FDA testing found a mean mercury concentration of just 0.024 parts per million, with many samples falling below detectable levels. For comparison, swordfish and shark typically range from 0.7 to 1.0 ppm. This makes catfish a safe choice for frequent consumption, including for pregnant women and young children who need to limit mercury exposure.
Farmed vs. Wild-Caught Catfish
Most catfish sold in the United States is farm-raised, and the nutritional differences between farmed and wild are modest. Wild-caught catfish tends to be slightly leaner with less saturated fat, while farm-raised varieties can contain marginally more omega-3 fatty acids because of fortified feed. The protein content is comparable either way. If you’re buying catfish primarily for protein, there’s no meaningful advantage to choosing one over the other.
Catfish for Weight Loss and Muscle Building
With 54% of its calories coming from protein and zero carbohydrates, catfish has a favorable profile for both fat loss and muscle-building diets. It’s not as protein-dense per calorie as something like chicken breast or cod, but it offers a flavor and texture that keeps meals interesting, which matters for long-term diet adherence. A 200-gram portion of baked catfish gives you roughly 32 grams of protein for around 235 calories, making it easy to fit into a calorie-controlled meal plan alongside vegetables or whole grains.