Compared with, say, “Toy Story,” this may not sound like the most remarkable premise for a movie. But the madly inventive folks at Pixar may just be the most dependable storytellers now working in Hollywood. The Wachowski brothers could learn a thing or two about suspense, economy, humor and pithy characterizations from the script by director Andrew Stanton, Bob Peterson and David Reynolds, which has the wit to dream up a 12-step program for sharks trying to kick their fish-devouring habits, and the ingenuity to have Marlin accompanied on his quest by a blue tang named Dory, whose eagerness to help is canceled out by her acute case of short-term memory loss. Ellen DeGeneres, hilarious and poignant, gives a tour de force reading.

The Pixar animators have outdone themselves in creating their luminous underwater world where everything is in constant motion. Much of the movie is like a hallucinatory scuba dive, but it’s equally eyepopping above the surface and within the superreal confines of the dentist’s tank, where Nemo and his fellow prisoners plot their high-risk escape. It all makes for a more satisfying adventure than “Monsters, Inc.” A visual marvel, every frame packed to the gills with clever details, “Finding Nemo” is the best big-studio release so far this year.