The Alewife and the blueback herring are almost identical, except that the Alewife has larger eyes.
The Alewife is green/gray color on the upper side of its body, with silver below. There is usually one small dark spot located on the upper side of the body, just beyond the gill flap.
They are smaller in size than American or hickory shad.
Although similar in length to a blueback herring, the alewives body is more compressed and less elongated giving it a wider girth than a blueback herring.