Guillermo del Toro’s “The Shape of Water” is like a beautiful painting you keep visiting at your favorite museum, because it continues to reveal its brilliant magic in new and different ways.

Set in 1962, this is a gorgeously color-coordinated fairy tale. Del Toro’s use of the color green alone is a wonder to behold, whether we’re taken aback by the almost neon glow of a piece of key lime pie, chuckling at the bright green shade of a plate of jiggling gelatin dessert, taking in the suitably aqua-tinged colors of the protagonist’s apartment, or appreciating the hue of a brand-new Cadillac.

“That’s not green, that’s teal,” says the slick salesman in the Cadillac showroom. “It’s the color of the future.”

So much of this film is about the clash of the past and the future, with America on the doorstep of a new and exciting and tumultuous age — but with one foot still firmly stuck in the past, battling the Russians at every turn, always looking for the upper hand. And what the general public doesn’t know won’t hurt them.

“The Shape of Water” is a Cold War-era “Beauty and the Beast” (with echoes of “The Creature from the Black Lagoon,” among other films). It takes place in the drab and yet somehow also electric Baltimore of the early 1960s, and it is a film that dares to be almost silly in its unabashed movie-style romanticism, and to the great credit of the writer-director and the wonderful cast, it succeeds at almost every turn.

Sally Hawkins, as fine an actor as you’ll see working these days, gives a sweet and funny and lovely and moving performance as Elisa, a mute dreamer who works the overnight shift as a maid in a top-secret government facility and falls in love with a mysterious sea creature that was captured in the Amazon and is now being held in shackles, tortured and prepped for execution and vivisection.

When will these short-sighted government types ever realize that if you come across a once-in-a-lifetime sea creature or alien being, you might want to spend some time observing its habits before killing the thing and cutting it up? That never ends well!

Actually, for being a such a top-secret government lab, the “Occam” Corp., as it’s known (a reference to Occam’s Razor?) is kind of lax on the whole security thing. I mean, they’ve just brought in an amphibious, gilled creature that looks like he’s half-man, half-fish—and yet they often leave it alone in a tank, shackled on a chain, with not a human in sight.

So without much interference, Elisa is able to strike up a friendship with Amphibian Man (Doug Jones). That may sound bizarre because it IS bizarre, but considering Elisa was an orphan whose throat was slashed as a baby, and who then was found literally floating in a river, perhaps she feels an innate kinship with the Amphibian Man before she can even understand it.

Elisa feeds him eggs; she sneaks in a turntable and plays romantic music for him; she teaches him sign language. Within a few days she’s positively giddy, and it appears as if Amphibian Man has feelings for Elisa as well.

Oh, but of course there are complications — complications beyond the whole “I’m a woman and you’re a fish-man” thing.

Michael Stuhlbarg is Dr. Robert Hoffstetler, a sympathetic scientist with a complicated backstory. Is he friend or foe?

Then there’s Michael Shannon’s Richard Strickland, the gung-ho G-man in charge of security. (And yes, this is another bug-eyed villain role for Shannon.) It’s already been established Strickland is a sadistic creep who gleefully uses a cattle prod on his prized capture — but after Amphibian Man bites off a couple of Strickland’s fingers (they’re sewn back on, with gruesome results), Strickland turns into a completely unhinged, pill-popping psycho.

Elisa has a couple of allies: her fellow maid, Zelda Fuller (Octavia Spencer, and yes, this is another sassy maid role for Spencer), and her across-the-hall neighbor, Giles (Richard Jenkins, simply terrific), a closeted, alcoholic advertising artist with a passion for watching glorious old black-and-white movies — particularly musicals — on TV.

And oh how those old movie clips play a role in later sequences in “The Shape of Water.” (This is a movie that loves so many different kinds of movies. In fact Elisa’s and Giles’ apartments are directly above an old movie house, which is failing miserably but is still a meticulously appointed architectural marvel.)

As “The Shape of Water” becomes a tick-tock thriller, with Elisa and her team desperate to save Amphibian Man and nefarious forces hell-bent on destroying him, I can’t say I was swept up in the love story. I found myself admiring and appreciating this film more than falling in love with it.

But I can certainly understand how this story will score a bull’s-eye to many a heart. It’s certainly one of the most romantic and one of the most breathtakingly beautiful movies of the year.

★★★1⁄2

Fox Searchlight presents a film directed by Guillermo del Toro and written by del Toro and Vanessa Taylor. Rated R (for sexual content, graphic nudity, violence and language). Running time: 118 minutes. Opens Friday at local theaters.