Fox Searchlight and director Guillermo del Toro have scored a decisive knockout in the copyright lawsuit over the Oscar-winning film The Shape of Water. A California federal judge on Tuesday rejected claims made by the family of late Pulitzer Prize-winning author Paul Zindel.

The lawsuit, filed on the eve of the Academy Awards this year, alleged that Shape of Water was a rip-off of Zindel's 1969 play called Let Me Hear You Whisper.

"The Court concludes that although there are some minor similarities, the Film and the Book are not substantially similar to the Play," writes U.S. District Court Judge Percy Anderson in Tuesday's decision to grant dismissal without any opportunitity for an amended complaint.

In the decision, Anderson examines the plot, setting, themes, pacing, mood, dialogue and characters in the respective works. He filters out what's not protectable before analyzing the alleged similarities.

For example, with regard to the plot, Anderson writes, "Although the Play and the Film share the basic premise of an employee at a scientific facility deciding to free a creature that is subjected to scientific experiments, that concept is too general to be protected. The same is true for the detail that the employee is moved by the subject’s impending death and the more basic idea of a person forming a connection with a non-human or animal. Other similarities stem from those basic and unprotectable elements, such as those responsible for the testing not seeing their work as harmful or wrong."

And there are notable differences, including the main character's relationship with the creature.

"In the Play, Helen does not appear to develop a unique attachment to the dolphin," writes Anderson. "Rather, Helen disapproves of animal testing, which leads to a desire to save the dolphin. By contrast, Elisa’s bond with the creature in the Film develops more slowly, growing into personal affection and then love."

Below is the full decision that provides a much fuller analysis of similarities and differences. The decision is also noteworthy in that Anderson refused to apply the "inverse ratio rule," which means that the greater the access, the lesser the showing of substantial similarity is required.

Anderson says he agrees with defendants "that regardless of the level of access that Plaintiff alleges, the level of similarity that must be shown does not change."

The plaintiff was represented by Marc Toberoff, while the defendants were handled by a legal team at Loeb & Loeb, led by Jonathan Zavin and Jonathan Strauss.