The epic journey required Marlin and Dory to leave the relative safety of the coral reef for the depths of the great unknown, which the filmmakers viewed as both a metaphor and the very real drop-off of a deep-ocean trench. “The ocean is so beautiful and there’s so much to explore, but if you’re a fish, every foot you go there is something that could eat you," observed producer Graham Walters. “Ultimately it comes down to anything could be out there. It’s both wondrous and terrifying.”