Credit for picture Nereids were beautiful young women who often rode the waves of the Aegean on the backs of dolphins, hippocamps, and other sea creatures. They were sea creatures but they did not have sea tails. They were friendly and protective of sailors. They could predict storms and guide sailors to good fishing grounds.
Thetis was one of the most famous of nereids. She was the mother of Achilles. Galatea was another famous nerieds, and she was beloved by the Cyclops Polyphemus. She did not return his love and instead choose a shepherd. Polyphemus, in his rage and jealousy, threw a boulder at the boy and crushed him. In her grief, Galatea transformed her mortal lover's blood into a river.