In order to have a good diet, one needs to include a lot of variety to ensure that you are getting the various nutrients that each food group has to offer. Fish and shellfish are an important part of the equation.
Fish is a high-protein, low-fat food that provides a range of health benefits. Fish are excellent sources of protein, vitamin B, vitamin D, trace minerals, and essential omega-3 fatty acids, which are lacking in most diets. White-fleshed fish, in particular, is lower in fat than any other source of animal protein, and oily fish are high in omega-3 fatty acids, or the “good” fats. Since the human body can't make significant amounts of these essential nutrients, fish are an important part of the diet. Fish are low in the “bad” fats commonly found in red meat, called omega-6 fatty acids.
The protein in fish is one of the best sources accessible. The Mayo Clinic online states that many red meats or poultry will have protein, but they also have more saturated fats, cholesterol, and calories than fish. Fish is able to offer the same amount or more protein and less of the negative attributes of meat and poultry.
For adults, at least two servings of omega-3-rich fish a week are recommended. A serving size is 3 ounces (85 grams), or about the size of a deck of cards. Women who are pregnant or plan to become pregnant and children under age 12 should limit the amount of fish they eat because they're most susceptible to the potential effects of toxins in fish.