The earliest poet to link Nereus with the labours of Heracles was Pherekydes, according to a ''scholion on Apollonius of Rhodes.
During the course of the fifth century BCE, Nereus was gradually replaced by Triton, who does not appear in Homer, in the imagery of the struggle between Heracles and the sea-god who had to be restrained in order to deliver his information that was employed by the vase-painters, independent of any literary testimony.
Nereus was known for his truthfulness and virtue:
The Attic vase-painters showed the draped torso of Nereus issuing from a long coiling scaly fishlike tail Bearded Nereus generally wields a staff of authority. He was also shown in scenes depicting the flight of the Nereides as Peleus wrestled their sister Thetis.
In Aelian's natural history, written in the early third century of the Common Era, Nereus was also the father of a watery consort of Aphrodite named Nerites who was transformed into "a shellfish with a spiral shell, small in size but of surpassing beauty."
Nereus was father to Thetis, one of the Nereids, who in turn was mother to the great Greek hero Achilles.