On our Vaisnava calendar, Wednesday 18th Sept is Ananta Caturdasi Vrata and the disappearance day of Srila Haridasa Thakur.
Although it is not indicated on our calendar to do so, according to Srila Prabhupada we should fast till Sunset on Ananta Caturdasi, see reference below.
Fasting on Ananta Caturdasi
(11th March 1972 Vrindavana Room Conversation)
Prabhupada: Yes. Bhaktivinoda Thakura 13th, and 14th Ananta Caturdasi and Haridasa Thakura. So, this 14th September should be observed fasting, whole day. [those dates relate to 1972. Fasting whole day refers to Ananta Caturdasi]
Devotee: Fourteenth is the advent of or the demise of Haridasa Thakura?