My Favorite Fairy Tales (Sekai Dōwa Anime Zenshũ) is a 1986 Japanese anime anthology by Saban, which retells various fairy tales including The Little Mermaid.
This version is pretty short and last just over 10 minutes, so it moves really quickly through the fairytale, not really giving the characters time to breathe. In this retelling, the little mermaid is not named, while her prince is Jonathan and the other princess is Elizabeth. The little mermaid's mother is alive in this one, too, which is really unusual, and there's some emphasis on mermaids not having a soul but being able to earn one if a human loves them.The pacing is really fast, and the little mermaid doesn't manage to carry out the minimum due diligence when pining after her prince, so once she has gained legs and brought the palace, she's given a shock when she learns that Jonathan and Elizabeth are already married. (I may have done a spit-take at that bit.)
The ending is also unusual in that it has the little mermaid literally being picked up by angels from the sea and carried into the sky. None of that spiritual stuff, y'all, the little mermaid is gonna fly right on out of the ocean in a bubble. That said, massive kudos for the narrator closing out the story with the little mermaid looking to the future, and hoping to find her own prince someday. Props for originality.
Watch the whole cartoon on youtube: HERE