Hilchos Chanukah - Laws of Chanukah
It is forbidden to fast during the eight days of Chanukah which begin on the 25th of Kislev. Even a Chosson (groom) on his wedding day is not allowed to fast. One would also not fast on the yahrzeit of a father or mother if it occurs during Chanukah.
--Shulchan Aruch 573:1, 670:3

One must be very careful with [the Mitzvah of] lighting Chanukah candles. Even someone who is supported by charity must borrow money or sell their clothes to purchase oil for lighting. This requirement is only to obtain enough oil for one candle each night

--Shulchan Aruch 670:1,3