Grade: B+

This summer Disney company goes “under the sea” once again, happily with a result that’s closer to the joy of “The Little Mermaid” than the stolidity of “Atlantis: The Lost Continent.” Pixar’s “Finding Nemo” is a sweet, beautifully fashioned tale of a father’s search for his son. It teaches about the importance of family ties, but does so with a puckish, generally gentle tone, which is interrupted by occasional bursts of raucously exciting action. And the predictable bid for tears is agreeably restrained.

The twist here is that parent and child are fish–clown fish, to be precise, though despite the designation, as is often the case in such stories they’re less funny than the secondary characters that surround them: other fish, a shark, some birds. There are also a few human figures on hand–a dentist (Bill Hunter) who puts the “boy” fish in his office aquarium, some of his patients and his terrifying young niece Darla (Lulu Ebeling), to whose not-so-tender care the young fish is destined to be entrusted (the fact that her entrance is accompanied by the shrieking violins of Bernard Herrmann’s “Psycho” music offers a clue to her character); in this case, though, they’re “drawn” in less naturalistic a style than in previous Pixar efforts, and so are less distracting and out-of-place.

The film moves along on two tracks that alternate with each other and eventually intersect. In one thread daddy Marlin (Albert Brooks), a cautious, overprotective sort who sees his boy captured by a diver and whisked away to parts unknown, goes through a series of adventures en route to Sydney, which he learns is the destination of the boat. (To be fair, he has reason to be circumspect: all of Nemo’s hundreds of siblings, along with their mother, were gobbled up while still in the egg stage.) Along the way Marlin encounters–among others–a shark named Bruce (Barry Humphries) who’s trying to conquer his fish-eating habit through a AA-style program, a bevy of dangerous jellyfish; an extremely laid-back turtle named Crush (director Andrew Stanton), along with his brood; a whale; some decidedly greedy and amusingly monosyllabic gulls; and a helpful pelican called Nigel (Geoffrey Rush). But his chief companion is Dory (Ellen DeGeneres), a voluble blowfish plagued–shades of “Memento”–by short-term memory loss (a gag that’s good for some laughs but overused). Meanwhile in separate action Nemo (Alexander Gould) is drawn into a scheme to escape back to the sea hatched by one of his aquarium-mates, the sea-wise Gill (Willem Dafoe) and involving their colorful fellow prisoners. Despite numerous obstacles and last-minute reversals, Marlin finds himself in Sydney harbor just as–through a stroke of good fortune–Nemo manages to get there, too.

This story isn’t much more than the kind of chase that might have served as the basis for a five-minute Loony Tunes short, but it’s been skillfully elongated with lots of cheerful incident and clever characterization. The dialogue isn’t consistently inventive–Marlin’s laments, for instance, grow a bit tiresome, especially when delivered in Brooks’s customary whining tones–but most of the vocal work is energetic (DeGeneres is an especially efficient sparkplug, but Dafoe, Rush, Humphries, Stanton, Gould, Allison Janey, Austin Pendleton, Stephen Root and others are excellent as well), and the clever gags and one-liners are sufficiently plentiful to keep things moving along nicely, even over the occasional longueurs. The computer-generated animation, moreover, is lovely–colorful, inventive and visually witty. It’s safe to say that while Disney’s more conventional animated efforts continue to suffer disappointing returns (“Atlantis” was a debacle financially as well as narratively, and even the far superior “The Emperor’s New Clothes” and “Treasure Planet” did poorly–only “Lilo & Stitch” beat expectations), this Pixar effort will be another “Monster, Inc.” hit.

Children and adults alike should be enchanted by “Finding Nemo,” as quietly charming, cheekily amusing a family feature as you’re likely to encounter this summer.