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Grouper is a firm, mild, lean white fish from warm reef waters, popular fried, grilled or in a sandwich. In USDA data, a 3-ounce portion of cooked grouper has about 100 calories, 21 grams of protein and about 1 gram of fat, plus a large share of the Daily Value for selenium. This guide covers grouper nutrition per serving, where grouper sits in the FDA and EPA mercury chart, why grouper fish appear on the FDA list of species linked to ciguatera, and what a lab study found when it tested fillets sold as grouper, so you can judge for yourself whether grouper is healthy for your plate.
Peptide Labs does not sell fish or seafood products. This article is general nutrition information, not medical advice. For a farmed Mediterranean fish that is often served whole, see our sibling branzino guide.
Key Takeaways
- Cooked grouper has about 100 calories and 21.1 g of protein per 3 ounces, with 1.1 g of fat (USDA).
- The same portion supplies 72% DV of selenium, 24% DV of vitamin B12 and 9% DV of potassium.
- FDA and EPA place grouper in their middle mercury group, labeled Good Choices, not the lowest group.
- FDA lists grouper among the reef fish linked to ciguatera, a toxin that cooking does not reliably destroy.
- In one lab study, only 12 of 70 fillets labeled grouper were confirmed to be grouper.
What is grouper fish?
Grouper is not one species. It is a market name for many fish in the family Serranidae, which is how the FDA seafood hazards guidance lists grouper. Many live around reefs in warm seas, and FDA groups them with other reef fish in its ciguatera guidance. The largest in US waters is the Atlantic goliath grouper, Epinephelus itajara. NOAA Fisheries says it can reach 800 pounds and 8 feet, can live more than 30 years, and that its fishery has been closed to harvest in federal waters of the southeastern United States since 1990, so the grouper on a menu is a different, smaller species.
Because so many species share the name, the USDA database has only a mixed-species grouper entry. The numbers below describe that blend, not one particular grouper.
Grouper nutrition per serving
USDA SR Legacy values for cooked grouper, mixed species, dry heat (FDC 171963), per 3-ounce (85 g) portion, with the percent Daily Value based on FDA reference values:
| Nutrient | Per 3 oz cooked (85 g) | % Daily Value |
|---|---|---|
| Calories | 100 kcal | n/a |
| Protein | 21.1 g | 42% |
| Total fat | 1.1 g | 1% |
| Saturated fat | 0.3 g | 1% |
| Cholesterol | 40 mg | 13% |
| Sodium | 45 mg | 2% |
| Potassium | 404 mg | 9% |
| Selenium | 39.8 mcg | 72% |
| Vitamin B12 | 0.59 mcg | 24% |
| Vitamin B6 | 0.30 mg | 18% |
| Phosphorus | 122 mg | 10% |
| Magnesium | 31 mg | 7% |
| EPA plus DHA (omega-3) | 0.21 g | no DV |
| Carbohydrate | 0 g | 0% |
A whole cooked fillet in the USDA portion table weighs 202 g and has about 238 calories and 50 grams of protein. The cooked entry lists no vitamin D or choline value, so none is given here. Raw grouper (FDC 171962) has 92 calories and 19.4 grams of protein per 100 grams in USDA data; cooking removes water, which is why the cooked numbers per gram are higher.
How grouper compares with other white fish
Per 3-ounce cooked portion, in USDA SR Legacy entries:
| Fish (cooked, dry heat) | Calories | Protein | Fat | EPA plus DHA |
|---|---|---|---|---|
| Grouper, mixed species (FDC 171963) | 100 kcal | 21.1 g | 1.1 g | 0.21 g |
| Tilapia (FDC 175177) | 109 kcal | 22.2 g | 2.3 g | 0.12 g |
| Atlantic cod (FDC 171956) | 89 kcal | 19.4 g | 0.7 g | 0.13 g |
| Halibut, Atlantic and Pacific (FDC 174201) | 94 kcal | 19.2 g | 1.4 g | 0.20 g |
| Atlantic salmon, farmed (FDC 175168) | 175 kcal | 18.8 g | 10.5 g | 1.83 g |
Grouper sits with tilapia, cod and halibut as a lean, high-protein fish. Oily fish such as salmon carry far more omega-3 fat; our omega-3 guide explains EPA and DHA.
Is grouper healthy?
On nutrients alone, grouper is a lean protein food: in USDA data it is low in fat and sodium, has no carbohydrate, and supplies a large share of the Daily Value for selenium, a mineral covered in our selenium guide. It also adds vitamin B12 and B6. Compared with oily fish, it is modest in omega-3 fat. If you are building meals around protein, our high-protein foods list and pescatarian diet guide show where fish fits.
The fuller answer depends on three things the nutrition label cannot show: mercury, the ciguatera risk FDA describes, and whether the fish is really grouper at all. Those are covered next.
Grouper mercury: where it sits in the FDA chart
The FDA and EPA advice about eating fish, revised in October 2021, sorts common species into three groups by mercury level. The chart is written for people who are or might become pregnant, those who are breastfeeding, and children. Grouper is in the middle group, labeled Good Choices, together with halibut, snapper, mahi mahi and striped bass. Cod, tilapia, catfish, flounder and sardines are in the lowest-mercury group. Swordfish, shark, king mackerel and bigeye tuna are in the group labeled Choices to Avoid.
This article does not repeat the chart’s serving advice. If the chart applies to you, read the FDA page itself or ask your clinician how grouper fits with the other fish you eat. People outside those groups can still use the chart as a guide to which species carry more mercury.
Ciguatera and grouper
Ciguatera fish poisoning is caused by toxins made by marine algae that build up in reef fish. FDA seafood guidance names grouper (family Serranidae) among the species linked to ciguatera, together with barracuda, snapper, jacks, moray eels and others. FDA notes that the risk is tied to subtropical and tropical reef areas and that fish caught side by side can carry very different toxin levels. Its worked example for seafood processors uses grouper: a lot should be rejected when its harvest area is under a ciguatoxin advisory.
A CDC report on ciguatera in New York City notes that ciguatoxins are colorless, odorless, tasteless and temperature-stable. In plain terms, you cannot see, smell or taste them, and the CDC report notes they are difficult to destroy, so cooking is not a reliable fix. FDA lists symptoms that typically start within 6 hours: nausea, vomiting, diarrhea, numbness or tingling of the lips, hands or feet, hot and cold sensations that feel swapped, and dizziness.
- Where it occurs: FDA says ciguatoxins are most common between latitudes 35 north and 35 south and have been found at unsafe levels in specific areas of Florida, Hawaii, Puerto Rico and the US Virgin Islands.
- Local catch: if you fish yourself, check state or territory advisories for the area before eating large reef predators.
- Symptoms after a fish meal: numbness, tingling or hot and cold reversal after eating reef fish calls for medical care; tell the clinician what you ate and where it was caught.
Grouper mislabeling: what lab tests found
Grouper is a high-value name, which makes it a target for substitution. In a 2008 study in Food Additives and Contaminants, researchers tested 70 commercial fillets labeled as grouper from local markets and supermarkets. Only 12 of the 70 were confirmed as grouper, and DNA testing found Nile perch in some of the others. One study cannot tell you how common substitution is where you shop, but it shows why buying from a seller who names the species and origin is worth the effort. FDA allergen rules also require packaged food labels to name the species of fish.
Cooking grouper and safety notes
- Cooking: FoodSafety.gov lists 145 degrees Fahrenheit for fin fish, or cook until the flesh is opaque and separates easily with a fork. Grouper’s firm, thick fillets hold up to grilling, baking and pan searing.
- Allergy: fish is one of the nine major food allergens under US law. A fish allergy usually covers grouper too; ask an allergist before trying any fish if you have reacted to one.
- Purines: if your clinician has asked you to watch purines, our purines guide explains how fish fits.
- B12: for more food sources of this vitamin, see our B12 foods guide.
Frequently Asked Questions
Is grouper healthy to eat?
In USDA data, cooked grouper is lean and high in protein, with 72% of the Daily Value for selenium per 3 ounces. It sits in the FDA middle mercury group and is a reef fish linked to ciguatera, so where it was caught matters.
How much protein is in grouper?
About 21 grams per 3-ounce cooked portion and about 50 grams in a whole 202-gram cooked fillet, in USDA SR Legacy data.
Is grouper high in mercury?
FDA and EPA place grouper in the middle group, labeled Good Choices. It is not in the lowest-mercury group and not in the group to avoid.
Can cooking grouper remove ciguatera toxin?
Not reliably. CDC describes ciguatoxins as temperature-stable and difficult to destroy, so cooking is not a safeguard.
What does grouper taste like?
Grouper has a mild, slightly sweet flavor and firm, flaky white flesh with large flakes, which is why it is often grilled or used in sandwiches.
Is all grouper the same fish?
No. Grouper is a market name for many species in the family Serranidae, and the USDA database only has a mixed-species entry.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Branzino: Nutrition, Farmed vs Wild and Is Branzino Healthy?, Red Snapper: Nutrition, Mercury, Ciguatera and Is Snapper Healthy?, Sea Bass: Nutrition, Chilean Sea Bass and Black Sea Bass.