The Mermaid Princess

This Chinese animated film The Mermaid Princess also has the title The Little Mermaid: Attack of the Pirates. It's a simple, light film for children about a mermaid named Annie who rescues a young girl, Sophie, after she's swept overboard from her father's ship. Annie's actions are forbidden by Poseidon, but she's insistent on saving the girl.

Annie decides to help bring Sophie back to her father, who's a Captain of the Royal Navy. Along the way Annie and Sophie encounter pirates, and Annie questions whether humans are good or bad.