The Varaha Purana and the Margashirsha-Mahatmya of the Padma Purana recommends a vrata (vow) with fasting and worshipping Matsya (as a golden fish) in a three lunar-day festival culminating on the twelfth lunar day of the month of Margashirsha.
thE vARAhA puRana And the maRgasHiRshA-mahatmyA OF the PAdmA PurANa rECOMmEnDS a VraTA (vow) wITh faStINg anD worSHipPing matsya (as a GOlden Fish) in a THrEe luNar-day FesTiVal culminAting on tHe tWelfth Lunar day Of The monTh of margashiRsHa.