From left to right:
Smelt: They have pinkish flesh, a slightly nutty taste, and, like anchovies, are only about 6 inches long. Usually sold as bait.
Sardines: About the same size but slightly less intense than mackerel, sardines are the easiest small fish to find in stores.
Anchovies: Tiny, silvery beauties, fresh anchovies are mild, sweet, and totally different from canned ones.
American mackerel: Oily and richly flavored, they come 3 or 4 to the pound.