Considering its diminutive size, the Black Sea anchovy (known as "hamsi" in Turkish) certainly creates a lot of waves, especially during the wintertime, when it is in season and readily available in Istanbul's fish restaurants.
Count the intrepid folks behind the great "Eating Asia" blog among those who have fallen under the finger-sized fish's spell. During a recent visit to Turkey, they not only tried the fish all over Istanbul, but decided to go on a quest to try hamsi at its source on the Black Sea coast. You can read about their delicious discoveries here. More on where to eat hamsi in Istanbul here.