Many people have the practice, on the yahrzeit of (especially) a parent, of bringing food to the synagogue so that others might recite b'rachos (benedictions) over eating the food after shacharis, which are meant to benefit the deceased. They call this food tikun n'shama, or just tikun.
It seems that the most common foods offered as tikun (in my experience in several Orthodox synagogues) are drinks, egg kichel, batter cake, and herring. Why herring?
- It's relatively expensive (certainly when compared to the kichel and batter cake).
- If the idea is to promote the recitation of b'rachos, herring doesn't help, as it shares b'rachos (fore- and after-) with the drinks.
- Although it's tasty, I don't think it will be missed terribly if absent. Herring without a drink or kichel would cause people to seek something to wash down the herring; kichel and a drink without herring is perfectly palatable and Part Of Your Complete Breakfast.
So why herring?