In Greek mythlogy, Nereids are the 50 daughters of the ancient sea god Nereus, and Doris, one of the 3,000 daughters that guarded the depths of the sea. They were said to be patrons of sailors, they were very protective of them and it was believed that they could predict storms and guide sailors to good fishing grounds. Nereids take the appearance of young, beautiful women, and are considered to be synonymous with Mermaids, however, unlike Mermaids they do not have fishtails. As opposed to swimming they ride naked on the backs of dolphins, sea horses and other marine creatures through the waves of the Aegean and other salt-water seas.

The most famous Nereids were Thetis, the mother of the Greek warrior-hero Achilles, and Galatea,who was beloved by the Cyclops Polyphemus.