Darla is the main antagonist in Finding Nemo.
Darla can't really be seen as truly villainous as she is just a kid and is not aware of her actions, but because she causes great harm to fish and supposedly kills it, she is feared by the other fish characters. She is the niece of Philip Sherman. Gill and other fish in Sherman's fish tank describe Darla as a fish killer and that Nemo is supposed to be her new pet fish. The last fish she got, Chuckles, was killed by her. In the scene where Darla is about to take Nemo from her uncle, Nemo plays dead, but Darla thinks he is just sleeping and starts shaking the bag. Gill then fires himself out of the tank and lands in her hair. She drops Nemo and his bag pops, and Gill knocks him into a drain leading to a sewer.