Next time you're trying to figure out what to have for dinner, go with fish instead of beef or pork. Your dinner will be lower in both saturated fat and calories and you'll get more of the essential omega-3 fats. Vary your fish choices to get the best mix of nutrients while minimizing any risks; both red snapper and tilapia can be healthy options.

A 3-ounce serving of snapper provides 109 calories, 1.5 grams of fat, 22.4 grams of protein and 40 milligrams of cholesterol. This amount of tilapia contains the same amount of calories, but slightly more fat, with 2.3 grams, and cholesterol, with 48 milligrams, and a little less protein, with 22.2 grams.

Both of these types of fish provide 17 percent of the daily value for phosphorus per serving, but red snapper contains more potassium, with 13 percent of the DV compared to 9 percent in tilapia, and tilapia has more selenium, with 66 percent of the DV compared to 60 percent in red snapper. You need phosphorus for proper kidney function and strong bones, potassium for nerve and muscle function and controlling your blood pressure and the antioxidant selenium for proper thyroid function and forming DNA.

Snapper is a bit more vitamin-rich than tilapia, with 50 percent of the DV for vitamin B-12 and 20 percent of the DV for vitamin B-6 in each 3-ounce serving. The same amount of tilapia provides 26 percent of the DV for vitamin B-12 and only 5 percent of the DV for vitamin B-6. However, tilapia does contain more niacin, with 20 percent of the DV per serving compared to 1 percent of the DV in snapper. Vitamin B-12 is essential for forming both DNA and the hemoglobin in red blood cells. Vitamin B-6 is important for protein metabolism, and niacin plays a role in circulation and forming certain hormones.

Red snapper and tilapia both provide omega-3 fats, but in different amounts. Red snapper is a better source of these beneficial fats, which may help lower your risk for heart disease and dementia. Each 3-ounce serving of red snapper provides about 200 to 500 milligrams of omega-3 fats, while the same amount of tilapia only contains about 115 milligrams. The Academy of Nutrition and Dietetics recommends getting an average of 500 milligrams of the omega-3 fats EPA and DHA, the types found in fish, each day.

When choosing which fish to eat, potential mercury contamination is an important factor to consider. Tilapia is among the fish lowest in mercury, and it is safe for pregnant women to eat up to 12 ounces per week and others to eat daily. Snapper is higher in mercury, but still one of the lower mercury fish which are safe for pregnant women to eat in amounts of up to 36 ounces per month and other adults to eat about three times per week.