"Once the month of Ab begins (=today) we minimize our happiness" mishenikhnas Ab, mema'atim besimha. These days are dedicated to prepare ourselves for mourning the destruction of our Bet haMiqdash. Therefore, in addition to the restrictions we mentioned for the three weeks (see this) we abstain ourselves from eating meat during these days. The shulhan 'arukh mentions that there are communities in which people do not consume meat and do not drink wine during the entire three weeks period while other communities restrict themselves only during the week of Tish'a be-Ab. In most Sephardic communities the tradition is to avoid eating meat during nine days; namely, from the second day of the month of Ab (tonight) until the day after Tish'a be-Ab (we will explain this later on). Some Sephardic communities avoid eating meat also during the day of Rosh Hodesh. Obviously, this restriction does not apply on Shabbat. On the contrary. It is forbidden to abstain from meat on Shabbat (except for health reasons). Fish is allowed during the nine days.
A person who is sick or weak, or a nursing woman during the first thirty days after giving birth, are allowed to eat meat during these. It would be preferable, if possible, if they eat chicken instead of red meat.
If a Se'udat Mitzva, such as Berit Mila, takes place during these days it is allowed to serve meat in it. Yet, in many communities meat was not served at a Se'udat Mitzva because the Shehita was discontinued once the month of Ab began and meat therefore was not available.
The Ashkenazi custom is to forbid shaving and cutting one's hair during the three weeks. In some Sephardic communities men do not get a haircut during the nine days. In most Sephardic communities men do not shave and do not cut their hair only during the week of Tish'a be-Ab.
Every person should follow his or her community and family customs.
Keep it delicious by pairing simple fishes with great strong flavors like tomato, garlic, mustard, and Parmesan cheese. by Elizabeth Kurtz, from Aish