Bastards. As if if weren’t enough to get me misty-eyed over stout-hearted action figures or itinerant insects, the masterminds at Pixar animation, previously responsible for both Toy Storys and A Bug’s Life (as well as the second-tier Monsters, Inc.), induce serious tearing up over the matter of cartoon fish in Finding Nemo. I’m all for a discreet tug at the heartstrings, but seriously, this is getting embarrassing.

Actually, it's the rest of the movie industry that should be embarrassed by Finding Nemo, which packs more emotional truth into a story about, yes, cartoon fish than any number of bloated, self-serious prestige pics or wannabe gritty indie mopefests. Despite the stigma, not even worth addressing, that brands animated movies as kids' stuff, Pixar's features have, from the beginning, addressed the process of leaving childhood behind from a subtly adult perspective. The toys in the Toy Story movies see what their owners do not: In their rush to be "grown up," they're discarding mementos that they'll one day pine for. (If the flashback in Toy Story 2 recalling the now-discarded cowgirl's halcyon days as a once-cherished toy didn't break your heart, you should probably check for a pulse.) Monsters, Inc. stumbled in its attempt to address the adult realities of work (not to mention a shadow version of unexpected parenthood), but Finding Nemo successfully manages the leap to the adult world. Our little Pixar is all grown up.

Written and directed by Andrew Stanton, who's had a hand in every Pixar feature since Toy Story, Nemo signals its intentions early on, with what might be the most traumatic animated maternal passing since Bambi scarred the Baby Boomers. Marlin (voiced by Albert Brooks) and Coral (Elizabeth Perkins) are a happy young couple of orange-and-white-striped clownfish, just moved into their new home in a sea anemone and eagerly awaiting the hatching of dozens of eggs, each of which seems to glow with its own inner promise. The sunlight, animated with breathtaking clarity, seems to filter straight through to the ocean's floor, and all is bliss, until a nasty fish with teeth like a drawerful of knives appears out of nowhere and makes straight for the eggs. Attempting to defend his brood, Marlin is knocked unconscious, and when he awakes, the eggs, and Coral, are gone.

All that remains is Nemo (Alexander Gould), whose egg somehow detached from the cluster and thus escaped the predator's notice. Had his siblings lived, he would surely have been, to mix a metaphor, the runt of the litter, with one underdeveloped fin that makes swimming an erratic adventure. But to Marlin, Nemo's the one rebuke to the feeling that he failed his paternal duties, and consequently overprotected as all get-out. Marlin coaches Nemo in poking his head out two, three, four times before leaving the shelter of home, and follows him uneasily to the first day of school, sure that something dreadful is going to happen. (If there's one emotion Albert Brooks knows how to play, it's free-floating anxiety.) Lo and behold, further trauma ensues, as Nemo, showing off in front of his new classmates, swims out into open water and is scooped up by a scuba diver, spirited away while Marlin swims helpless against the prop wash of a rapidly disappearing boat.

The rest, of course, is adventure: Marlin swims the ocean, desperately searching for his lost spawn, while Nemo plots escape from a dentist's aquarium, dreading the imminent arrival of his careless niece, who's shaken many a previous "present" to death. Nemo finds camaraderie in the tank -- with, among others, Gill (Willem Dafoe), a veteran of several escape attempts -- while Marlin hooks up with Dory (Ellen DeGeneres), an absent-minded fish who can't remember anything other than her own name: Like a dizzy version of Memento's Leonard, she'll be fleeing, say, an enraged shark, then suddenly forget what she's doing, turn around and say, "Hey look! A shark!"

That Dory's more childlike than Nemo is surely no accident, and the bond that develops between her and Marlin is a sweet, contentious one. Brooks and DeGeneres square off against each other with the riotous ease of seasoned comedians; it's no slight on Pixar's increasingly impressive animation that one of Finding Nemo's most blissful moments comes when Marlin and Dory dive into a lightless trench, and for a moment you're left with only the two performers' perfectly pitched voices playing out against a black screen. Brooks, of course, proved his skill at voiceover work as far back as The Simpsons' first season, but I can't ever remember laughing so hard and so consistently at DeGeneres as I did here. After her all-too-public coming-out and subsequent turn under the media microscope, you can almost sense DeGeneres glorying in the chance to push her comic talents back to the fore. (Of course, conservative Christian groups have seized the moment to protest that it's "inappropriate" for an out lesbian to give voice to a character in a children's movie; they may, to use the appropriate term, stick it in their blowholes.)

Humans make an appearance in most of Pixar's films, sometimes as disembodied appendages, sometimes as incomprehensible creatures with mysterious habits. But it's a smoke screen; they focus our attention on the unrecognizability of humans so we don't notice how we're covertly being coaxed to identify with toys, bugs, monsters and fish. Pixar's creatures have humanity that most flesh-and-blood movies can't touch.

Written and directed by Andrew Stanton A Disney release Opens Friday at area theaters