As tomorrow is Zayin Adar (and I'm a bit fed up with PTIJ), I was trying to find sources that Moses was born and died on Zayin Adar, and it was more difficult as it is widely known. For the record, it was already discussed on Mi Yodea based on Kiddushin 38a and partially on Sotah 13b. However, I know three customs (usually performed at the same event), but I don't know of sources citing them:
- Eat fish, since the gematria of דג is 'ז (see also for Shabbath) and the מזל of Adar is the fish (see Rambam)
- Commemorate the people, who deceased in the last year
- Collect funds for the Chevra Kadisha, since Hashem buried Moses (see Rashi to Devarim 34:6 based on Sotah 13b)
- Omit tachanun (a much debated practice that is not mentioned in Orach Chayim 131:6)
- Fast (see Orach Chayim 580:2 and this article)
Do you know any sources that mention them?