Grouper comes in numerous varieties, colors and sizes. Like most fish, grouper contains large amounts of protein, minimal amounts of saturated fat and no sugar. Unlike fatty cold-water fish, grouper does not supply large amounts of healthy omega-3 fatty acids. Grouper can also carry a toxin, ciguatera, which can cause neurological problems if you ingest it. Most fish, including grouper, are naturally low in calories. A 3-ounce raw serving of grouper supplies 100 calories. Fish serves as an abundant source of protein. Grouper contains 16.5 grams of protein in a 3-ounce cooked serving of fish, which equates to just over 25 percent of your daily recommended intake of 50 grams of protein per day. Grouper contains a small amount of the omega-3 fatty acids DHA and EPA, although not nearly as much as fish such as salmon, mackerel or herring, according to the Minnesota Sea Grant. Grouper, like other fish, serves as an excellent source of some vitamins and minerals and also contains low amounts of minerals such as sodium.