The name of fairy tale author, Hans Christian Andersen is spelled incorrectly at the beginning of the film as "Anderson".
The swallows, Cecil and Claudia, switch voices during two of their lines when they discover Lena coming out of the water. Claudia, the female swallow with long eyelashes speaks with Cecil's voice and vice-versa.
After the hand-shaped creatures release Lena's and Vink's tails, Cassandra, referring to Vink says, "I didn't say anything about you, dolphin." However, moments before she had indeed said "Let go of them," referring to both Vink and Lena.