Aquatatic was born in Equantica as an alicorn princess. She was a playful little baby, and when she got into her filly years, she never found it very grand being a princess, and wanted to try something new. But when she realized that she could do new stuff even as a princess, she decided to try it out. She helped her parents out with deciding what to do with a criminal who was only stealing food for his poor family, and it worked. The prisoner was freed, and Aquatatic got her cutie mark, a crystal heart inside a trident.
When Aquatatic grew up years later, she came to see the birth of her newborn sister, Marenia. She and her brother, Prince Aquatos, would babysit Marenia while their parents were gone. Years later, Marenia grew up, made new friends, and became a princess. However, things changed when Equantica was cursed during Discord's reign. The entire city was sent under the seas of Destiny Islands.
Years later, the city was invaded by pirates lead by the infamous Captain Taiklar Blackheart, and robbed of many treasures, including the Trident of Benevolence, which kept Equantica's friendship, kindness, and forgiving of land creatures flowing. Aquatatic lost her father, and her mother was almost killed. The ship fled when the Purple Sea Dragon Guardian of Equantica attacked. Unfortunately, thanks to Dead Sea, the Purple Sea Dragon was killed, and no one ever knew about it. Not even Aquatatic.
After this, Aquatos, Aquatatic, and Marenia were cast with a spell by their mother to keep their kindness and compassion for land creatures flowing. Years later, Dead Sea took away Marenia's wings, and the spell protecting her from the curse as punishment for flirting with a Destiny Islands horse prince named Derek. She was soon unsympathetic against land creatures, especially when Geogra comes in and turns them against them. Since then, Aquatos and Aquatatic have been trying to help Marenia any way they can. That is until a certain yellow pegasus pony wishes to see life underwater, and becomes a merpony in exchange for helping them.