When I was younger say early 80s I saw a movie that featured a girl walking by the water and falling into it , which becomes a cartoon based movie with adventures ending with her getting out of the river/ body of water being real again ? When she was a cartoon she was able to interact with the fish ? That is all me memory has at this time can you make anything out of this?

Was it The Water Babies? The Water Babies (1978) (http://imdb.com/title/tt0078477/)