Tethys was a Titan goddess of all the fresh water on earth. She was one of six daughters of Uranus and Gaea. She appropriately married Oceanus (personification of all the salt water on earth) and, according to Hesiod, they gave birth to three thousand Potamoi or river gods and Oceanids, known as nymphs of seas, rivers, lakes, streams, fountains, and marshes. She was also believed to be nursing and feeding her children by drawing water from Oceanus through subterranean channels and also taking care for all creatures living in the waters such as fish, seals and dolphins. During the war between the Titans and younger Olympian gods Tethys was believed to had been raising Hera as her step-child. According to Claudian she is also said to had been taking care of Helios and Selene. In art she is often depicted with a small pair of wings just above her eyebrows which probably presents her not only being a mother of rivers, streams and other supplies of fresh water but also as a mother of Nephelai (rain-clouds) and Aurai (breeze) who are associated with Sky deities.
Deception of Zeus
Tethys is not directly involved in this myth but is just used as an excuse by Hera. She appears in the Homer's epic of Trojan war where Hera deceived Zeus in order for other gods to involve in the battlefield, despite the direct order of Zeus not to involve. Hera lied to Zeus by telling him that she was going to visit Tethys and Oceanus. Instead she went to Aphrodite who helped her to beauty herself and prepare a seduction plan. Hera then seduced Zeus and made love with him until exhaustion which gave a window of opportunity for other gods to interfere in the battlefield and consequently for the Greeks to regain an upper hand in the war.
Oceanids and Potamoi
As mentioned above Tethys was a mother of three thousand Potamoi or river gods and three thousand Oceanids or water nymphs. Here is a list of the most known Oceanids and Potamoi:
Potamoi (river gods)
Oceanids (water nymphs)