The film was released about 115 years after Charles Kingsley's source novel of the same name, first published in 1863.
Charles Kingsley wrote "The Water Babies" book for his son, it being a children's fairytale novel, in the vein of Charles Dickens and a part satire supporting Charles Darwin's "The Origin of the Species".
Filmed in 1976 but not released until 1978.
The full title of the movie's source book was "The Water-Babies, A Fairy Tale for a Land Baby".
Samantha Gates is the nude girl in the artwork for Led Zeppelin's album 'Houses of the Holy'. She is also the model in Hajime Sawatari's 1973 book "Alice".