Story From Ramayan - Makaradhwaja -Sweat -Hanuman -Mermaid
Few versions of Ramayana mentions a mermaid, who accidentally swallowed the sweat of Hanuman, who was crossing the sea towards Lanka. She delivered hanuman’s son Makaradhwaja; who becomes the gatekeeper for Ahiravan in Patalalok. No name of this mermaid was mentioned.
But Thai versions mentions her as Suvarnamaccha or Suvaranamatsya. They mention her as Ravan’s daughter, who purposefully tried to fail sethu bhandhanam. when Hanuman finds about this mermaid princess, he reveals the reason for building the bridge & she stops her plans.
The part away as lovers & Hanuman has a son in her named Macchanu. In Mahabharata, an apsara named Adrika was cursed by a sage to become a mermaid[few version says as a fish]. She will be revealed from her curse after delivering two babies. Uparichara vasu was the king of chedi.
Once during his hunting in the forest, he desires his beautiful queen. He collects his semen in a leaf & sends this to his queen in the palace through an eagle. On the way, the eagle fights with another eagle.
The semen fells on water, which was swallowed by a mermaid called Adrika. Adrika gives birth to two kids. A boy & girl & Adrika gets liberation from her curse. Dushraj the chief fisherman was her brother. He gives the babies to the king of the chedi.
King accepts the boy & gives the girl to Dushraj. The girl who grows up as the adoptive daughter of Dushraj, was Satyavathi, wife of Shantanu & step mom of Bhishm .