Studio 54 could be a real zoo.

Though many were turned away at the door of the late, great NYC icon — which opened 45 years ago April 26, 1977 — plenty of animals managed to get in.

“The live leopard was my favorite — a couple brought it in on a leash,” recalled Gerard Renny, who landed a gig working security at Studio 54 when he was just 18. “They said I could pet it and needed to keep guests away from it.”

“I guess I was its bouncer-bodyguard that night,” said Renny, 63, an Upper East Sider who is now director of operations at the ‘70s-themed watering hole Ethyl’s.

There was also a snake — the plus one of another guest — slithering at the bar one night.

“I got called in to come to the main bar because someone said there was a boa constrictor there,” said Chuck Garelick, who was 19 when he started as the head of security at Studio in 1977. “It turned out not to be … but it was a very large, very long snake that someone had brought in their bag.”

But some animals gained entry on the orders of club owners Steve Rubell and Ian Schrager.

“There was one Halloween where the front lobby was decorated as a fun house, and it had a maze on the floor that was covered in plexiglass, and there must have been a couple hundred white mice,” said Garelick, 64, who now lives in Union Square and is a security executive.

“It was all blacklights, so they put a stripe of UV paint [on the mice]. After we cleared that out, they were around that place for a long time. We had white mice running around for months,” he said.

Things got a little fishy on Valentine’s Day in 1979, when management installed metal fish ponds in the lobby.

That night, a fire at a different Manhattan club sparked surprise FDNY inspections. They ordered the club to get rid of the goldfish-filled ponds.

“So a bucket brigade was formed with all kinds of staff, security and the busboys — who at the time were wearing short shorts, sneakers, no shirts and angel wings,” Garelick recalled.

“We poured [the ponds] right onto 54th Street, not even thinking about the goldfish,” he said. “It was really cold that night, and when we left that morning, there were frozen goldfish all over the curb.”

The club shut down in 1980 after the founders were convicted of evading taxes, and operated under new ownership from 1981 to 1986. Ex-Studio employees — who call themselves the “Class of 54” — are gathering at Ethyl’s on April 24 for an anniversary and reunion party. Some recalled bringing their own pets past the velvet ropes.

“During the day if you worked at Studio you could bring your dog to work,” said Myra Scheer, who was in her mid-twenties when she worked as executive assistant to Rubell and Schrager,

There was a trio of canines — Scheer’s English shepherd Mateus; Friend, a setter who belonged to Neil Wilson on the tech crew; and Pepe, a chow that belonged to Studio’s private party booker, Shay Knuth — that had free reign.

Scheer, 71, who now co-hosts “The Marc and Myra Show” on Sirius’ Studio 54 Radio, said, “The most glamorous, exclusive place in New York City at night had three regular dogs that roamed the dance floor.”