"To find out what their fish could and couldn't do, Stanton and his crew installed a fish tank and filled it with clown fish and blue tang, among others. Some became scuba divers to study their subjects more closely. They hired a "fabulous fish guy," Adam Summers, professor at the University of California at Irvine, who schooled them in the two types of swimming fish: rowers, who move their fins back and forth, and flappers, who move theirs up and down. By coincidence, Stanton had chosen one of each kind — a rower clown fish and a flapper blue tang — as his leads.
Any education is the process of learning how little you know. The Pixar animators had to learn a lot about what Stanton calls "the voodoo of underwater things. Things lose color when they go away from you and gain color when they come closer to you. There's crap in the water, and surge and swell." All this had to be analyzed or guessed at. "It was like somebody gave you a cake and said, 'O.K., figure out what ingredients it takes to make this,' but with no cookbook. And you're just going, 'I think I taste egg ... I think I taste sugar ...'"