Colin Farrell and Alicja Bachleda dated while shooting the film, and had a son a year later. But they broke up in 2010.
When Ondine is wrapped in the Mylar blanket, the wind gives the appearance of her having a fish-tail.
The song played with the closing credits is Lisa Hannigan's "Braille." For some time the song was available for subscribers of Hannigans newsletter. An official release did not follow.
Stephen Rea plays a minor role in this film, and he also had a starring role in a similar "mermaid" film released in the same year, Nothing Personal (2009)