King Nimi asked Yogi Karabhajana about how Vishnu was worshipped and how He should be worshipped. Yogi Karabhajana told King Nimi that in each yuga, Vishnu was worshipped in different forms, explained P.T. Seshadri in a discourse.
In the Krita yuga, He was white in colour, had four hands and He wore garments made of the bark of trees. In Krita yuga, people led peaceful lives. They were gentle and did not fight with each other. They had control over their senses. They performed tapas and reached the Lord’s feet. In this yuga, the Lord was known by ten names: Hamsa, Suparna, Vaikuntha, Dharma, Yogeswara, Amala, Iswara, Purusha, Avyaktah and Paramatma. In Treta yuga, He was red in colour, with hair of a golden hue. He had four hands and there were three folds in His stomach. He had in His hands sruk and sruva. These were wooden ladles used for pouring ghee into the sacrificial fire. People were adherents of dharma and were knowledgeable in the Vedas and praised Him through Vedic hymns. He had eight names in Treta Yuga: Vishnu, Yajna, Trishnigarbah, Sarvadevah, Urukramah, Vrishaakapihi and Urugaayah.
In Dwapara yuga He was green in colour and wore silk garments. He held in His hands weapons like the conch, discus and mace. In His chest was the Srivatsa. He was adorned with the Kaustubha gem. In this yuga, He was worshipped in four forms: Vasudeva, Sankarshana, Pradyumna and Aniruddha. He was known by the following names: Visvesvara, Visvaroopah and Sarvabhootatma. In Kali yuga, He is black in colour. In this yuga, He is praised through Nama Sankirtana. Through Nama Sankirtana, people can get worldly benefits and also attain moksha. Because of this, the sages of Krita yuga will desire to be born in Kali yuga, so that they can sing His praises, said Karabhajana.