Anantha Vratha is observed on the Chadurthasi day, Shukla Paksha, Badrapada masa. This pooja is dedicated to Lord Vishnu in Anantha sayana form on the serpent bed of Aadisesha. He reclines relaxedly and creates Brahma from his navel and srushti began in the world through Brahma.
Anantha means endless. To get endless happiness and peace this pooja is performed by married couple. Normally this vrata is observed for 14 consecutive years. According to Purana, Krishna advised Yudhishtra to perform pooja for 14 years during their vanavasa to get back their lost kingdom. A legend says that King Harichandra performed this pooja to get relief from sorrows. As per another legend, Nala-Dhamayanthi performed this pooja to get back everything they lost.
Some people keep kalasa and do pooja. Others can keep a photo of Anantha Padmanabha swamy and perform pooja. We have to keep Anantha Dhara in front of God and do pooja to that also. This dhara contains 14 strands. In pooja shops, Anantha dhara for men and women(red colour sacred thread) is available. While doing pooja 14 dharbas are offered to God. The neivedhyam normally prepared are wheat payasa and wheat dosa. Vishnu Sahasranama, Purusha Sooktham and Vishnu Sooktham are to be recited.
An important point is tying the red sacred thread after pooja. For men, the dhara is tied on the right arm and for women, on the right wrist.
Happy Anantha vratha.