None.

There is some disturbing violence, all involving any kind of fish. This include: gory fish slaughtering, some kinda graphic cannibalism, heated arguments leading towards violence, and fish being killed by multiple crabs.

A few minor swears like "Bastard".

If rated by the MPAA, this movie would likely receive an PG-13 rating for intense violence/torture towards animals, disturbing grisly images, and some strong language. It's listed as 13+ on Amazon Prime.

Suggested rating PG-13 for disturbing violence and grisly images

While this film looks like a harmless Disney-movie, this Korean animation may disturb younger children, because of the violent content all involving fish.

Several fish can be seen struggling for life as they try to escape the aquarium, where they are often seen throughout the film. They have been caught in order to become food for people.

The audience is able to see a fish slaughtering seen through any fish character's point of view. An example is the scene in which a sole is about to get chopped up by a butcher, and you can see the sole looking in fear of being butchered.

Some younger people may not want to eat fish anymore because of the content written above.