The Podvig [ascetic feat] of the Apostles' Fast is less strict than during Great Lent: We abstain from eating meat and dairy products throughout the Fast. The Church ustav [rule] also provides that, on Mondays, Wednesdays and Fridays during the Apostles' Fast, we abstain from consuming fish, wine and oil; on the other days of the week, Tuesday and Thursday, we abstain from eating fish. Eating fish is permitted on Saturdays and Sundays, on days commemorating certain great Saints, and on the Feast of the Nativity of St. John the Baptist (7 July).Even more succinct:
Apostles' FastI should add a few points of leniency. According to the Typikon, if on Monday, Tuesday, or Thursday a saint is celebrated with a Doxology service (or above), then fish is allowed. If such a saint is celebrated on Wednesday or Friday, then wine and oil are allowed. And if on Wednesday or Friday a saint is celebrated with an All-Night Vigil, fish is also allowed.
The rule for this variable-length fast is more lenient than for Great Lent.
Monday, Wednesday, Friday: Strict fast.
Tuesday, Thursday: Oil and wine permitted.
Saturday, Sunday: Fish, oil and wine permitted.