(Note: In view of this film’s wide exposure for nine years, this review is somewhat less spoiler-sensitive than most of my reviews. — SDG)

Andrew Stanton’s Finding Nemo is the best father-son story in all of Hollywood animation, and maybe animation generally. It’s also a stunningly gorgeous film that exploits the potential of computer animation like no film before it and few films after it.

I can imagine the Toy Story films or Monsters, Inc. or Shrek being made as traditional hand-drawn animated films — or as stop-motion, for that matter. They would lose something, but perhaps also gain something; and while they wouldn’t be the same, I can imagine the essence of the films surviving.

Finding Nemo couldn’t be anything other than computer animation, because its essence is inseparable from the splendor of its undersea world, realized in quasi-photographic grandeur and richness unmatched by the noblest attempts of hand-drawn animation (Disney’s “Arab Dance” fish in Fantasia’s “Nutcracker Suite” sequence; The Little Mermaid; even Miyazaki’s Ponyo). No previous computer-animated film was so specific to this medium. Of later films, perhaps only Cars and Stanton’s own Wall-E are so dependent on texture, depth and the ambient quality of atmosphere itself — or, in the case of Nemo, of water.

Watching Nemo in 3-D on the big screen with my kids, I was captivated by all sorts of details that don’t stand out the same way on the small screen: the varying degrees of transparency and translucence of fishy fins; the articulation of the tiny suction cups on the underside of Peach the starfish in the dentist’s fish tank. Look closely at the top of the little pink octopus with one slightly shorter tentacle: Her mantle is slightly transparent.

Then there’s Mr. Ray’s tour of the coral reef — one of the most eye-popping, kaleidoscopically colorful sequences in all of animation, from the flashing reflections of his own spotted back on the surface just above him to the heightened naturalism of the flora and fauna (the Spanish dancer sea slug is a favorite). Cartoony character design notwithstanding, Finding Nemo has a love for the natural world that’s a credit to the tradition of Bambi and The Lion King. (Contrast DreamWorks’ Shark Tale, which is full of clever submarine conceits (e.g., the Whale Wash), but is too wedded to the surface world to honor the wonder of the ocean.)

The other thing linking Finding Nemo to Bambi and The Lion King, of course, is not one but two of the most traumatic parental separation/loss scenes in all of family cinema. What makes Nemo different is that these scenes are depicted not from the child’s point of view, but from the father’s.

Finding Nemo solidifies the orientation of previous Pixar films as family films aimed at parents. The Toy Story movies were about parental anxieties (or at least Toy Story 2 was); and Mike and especially Sully in Monsters, Inc. were for a time the grown-ups in Boo’s world (if less surrogate parents than avuncular figures in a sort of Two Monsters and a Baby scenario). Finding Nemo dispenses with surrogate relationships: It’s a literal father-son story transparently set amid the aspirations and anxieties of American suburbia and helicopter parenthood, though transposed to an undersea world of anthropomorphic fish.

The film is named for the son, but the titular quest is the father’s. Marlin (Albert Brooks) is the hero: a flawed but deeply sympathetic widowed father, scarred by tragedy and loss and anxiously overprotective of his only son, Nemo (Alexander Gould), who has a slight handicap — an underdeveloped pectoral fin.

It all stems from a tragic prologue set in the fashionable neighborhood on the edge of the coastal shelf overlooking the Drop-off, where Marlin loses his beloved wife Coral (Elizabeth Perkins), his confidence (“A fish can breathe out here!” he declares expansively before learning to fear the Drop-off) and all but one of their 400-plus eggs. (This heartbreaking sequence makes effective use of point-of-view shots, from the chilling vision of anemone tentacles drifting lazily at the wrong angle, desaturated by the sinking sun — a marker of time lost in unconsciousness as well as mood — to the throat-lump-inducing shot of Marlin’s fins cradling that infinitely precious last egg, an image with powerful nascent pro-life resonances.)

Needless to say, little Nemo grows up in a new anemone far from the Drop-off, and the one lesson he has learned above all others is that the ocean isn’t safe — though this hasn’t dampened his desire to venture out into the world he instinctively knows he must confront sooner or later. There’s the theme of the conflict, though Stanton makes clear that Marlin’s overprotectiveness hasn’t soured their relationship or taken the tenderness and playfulness out of it. (Contrast Brave, where Merida’s relationship with her mother, at least in the first-act present, seems lacking in anything but conflict.)

Then comes another fateful day at the Drop-off. It’s a fascinating scene, among other reasons, for its layered depiction of filial obedience, defiance and consequences. Nemo knows he probably shouldn’t be at the Drop-off with his new friends at all, but when it comes to their little game of chicken, swimming a few inches off the coastal shelf, he defers to his dad’s wishes. Alas, Marlin doesn’t see it that way, and his peremptory dressing-down prompts Nemo’s understandable but disastrous defiance.

Separated for most of the film, both Marlin and Nemo are stretched by new acquaintances who implicitly challenge Marlin’s micromanagerial parenting style. In the dentist’s fish tank Nemo finds a secondary male role model in Gill (Willem Dafoe), a crusty striped fish (a moorish idol) who pushes Nemo beyond his comfort zone and offers no sympathy or coddling for his bad fin. Marlin meets Crush, a surfer-dude turtle whose laid-back parenting style befits his species’ habit of leaving youngsters to fend for themselves.

And, of course, there’s Dory (Ellen DeGeneres), a flighty blue tang who knows how to live in the moment because she can’t remember anything else. Her short-term memory loss is the source of much hilarity, though it also connects with the movie’s theme of handicaps and infirmities (the very funny 12-step sharks are another example).

Perhaps that’s why Marlin unconsciously transfers his parental anxieties to Dory. You can see it as he tries, with all the euphemistic gingerness and flat-out dishonesty of a guilt-wracked parent trying not to crush a child’s self-esteem, to part ways with Dory. (“And sometimes it’s a good thing! There’s a whole group of fish — they’re called delay fish …” Note the same euphemistic delicacy in Nemo’s “lucky” fin.)

And then, of course, the moment of emotional truth, clinging to a taste bud on a whale’s tongue, as Marlin resists Dory’s unknowingly fraught exhortation that it’s “time to let go”: “You think you can do these things, but you just can’t, Nemo!” Marlin’s eyes widen as he realizes what he’s said.

There’s also a wide-eyed moment of truth for Nemo as he realizes that there is more to his father than he ever guessed. For all his foibles, Marlin is genuinely heroic — reluctantly and frantically at first, but with a grim warrior resolve by the end. (His two hardiest moments are in the gullets of pelicans. After putting in time in the maw of a whale, he isn’t about to be pushed around by some pelican.) That moment when Nemo first begins to believe in his dad … I cried the first time I saw it in the theater nine years ago, and it still gets me every time.

But it’s not enough that Nemo believes in his father. Marlin also has to learn to believe in his son. For all his adventures, the bravest, hardest thing Marlin has to do is let Nemo go into danger alone. However old and experienced Nemo may be, how can Marlin ever look at him and not think of that precious, scratched egg in his fins?

There are head-scratching bits, such as Dory’s ability to read, a random plot convenience. Go with those, though, and the story is the height of Pixar polish and economy. Every scene, and practically every line, propels the story forward; the episodic adventures are one splendid set piece after another.

For all that, what makes Finding Nemo so unforgettable, in my book, is Marlin. He stands virtually alone among animated father figures: not an idealized father, but a heroic and lovable one who is trying his best and whose faults, such as they are, are regarded with sympathy and understanding. At the very end, Nemo tells his father, “I love you, Daddy.” In what other cartoon does that simple declaration carry so much weight?

P.S. Finding Nemo 3-D is preceded by “Partysaurus Rex,” easily the funniest and most inventive of the Toy Story shorts.

Steven D. Greydanus is the Register’s film critic.

Content Advisory: Animated high excitement and menace; parental separation theme. Could be frightening to sensitive youngsters.