2021-07-28 · According to the American Heart Association, a serving of fish or seafood is about 3 ounces, but that can vary, depending on appetite and whether you are feeding young children. 1 Allow about 4 ounces for each adult and about 2 ounces for small children. If the shrimp are unpeeled or head-on, such as in a shrimp boil, allow roughly 6 to 8