Since “Piranha 3-D” opened in almost 2,500 theaters two summers ago, when the sequel turned up on this week’s calendar, it seemed a foregone conclusion that it would get the same treatment.

After all, “Piranha 3-D,” a remake of the ’70s cult classic “Piranha” (which was filmed in San Marcos), got surprisingly good reviews. Lots of critics praised it as an over-the-top guilty pleasure. And word was the sequel would do what sequels always do — double down on everything. In this case, that would be violence and nudity (as “three double-D” in the title suggests).

But if you want to see it in San Antonio (it opens Friday), you’ll have to go the video-on-demand route. Strangely, the studio, Dimension Films, is opening “Piranha 3DD” in only 75 theaters nationwide. None of those is in the Alamo City. The closest theater is the Alamo Drafthouse’s South Lamar location in Austin. It’s also showing at one theater in Houston and a couple in Dallas.

Not exactly sure what happened, but the film has received scant publicity. “I never even saw a trailer on tv, cable or anywhere, for it, bad promotion,” a guy named Richard Chirico wrote on the movie’s Facebook page.

Others noted the movie’s head-scratching scarcity. Sample comments: “..not coming to Cleveland..,” “not coming to the Twin Cities, either” and “nothing in CT; (bleep) this movie.”

Part of the problem is that some movie chains — notably Regal Cinemas, which has five San Antonio multiplexes — won’t show movies also available through video on demand on opening day. As this observer pointed out, this came up during “Tower Heist” last year; that studio eventually backed down.

Some of the folks involved with the movie are doing publicity, though. The Associated Press interviewed director John Gulager and screenwriter Marcus Dunstan. One Dunstan quote tells you everything you need to know about the movie (although you can always check out the redband trailer if you doubt his word):

“We wanted to double everything. If the first one had laughs, we wanted to double the laughs. If the first one had violence, we wanted to double the violence. If the first one had offensive elements, well, actually, we wanted to triple the offensive elements. That was always the DNA of this movie.”

The premise is certainly laughable. While the vicious fishies of “Piranha 3-D” were unleashed in a desert lake by a seismic event, which seems at least a bit plausible, the new batch seems to be able to travel through any water source — municipal pipes, bathtub faucets, etc. But mostly they wreak havoc at a naughty water park called Big Wet, where strippers are the lifeguards and David Hasselhoff is in no way interested in doing anything heroic — like rescuing the young nubiles being torn apart in front of him (he actually has a Darwinian take on the events).

The piranhas also seem to be able to be whatever size is required to inflict maximum damage, including shrinking to the size of that nasty little Amazon menace, the candiru, which allegedly can swim into very sensitive and intimate areas. The trailer suggests that one of the toothy guys gives one of the film’s young hotties an accidental case of vagina dentata.

Yikes! That’s gotta hurt.

And (mild spoiler alert!) apparently by film’s end, the title characters don’t even need a water source anymore. Can you say “Landshark?”

Anyway, David Koechner, who plays the sleazebag running the waterpark, is out there stumping for the movie, too. He gave a revealing quote in this interview with the Huffington Post.

After describing the movie as “pretty raw,” he was asked:

When you were offered your first horror movie, were you at all hesitant?

No, I was not hesitant. I have a wife and five children, so, if there’s work, chances are Daddy’s going to go do it.