Tourists leaned over the ornate stone and iron railings, surprised that the 280,000 gallons of water that normally course below the cobblestone walkways was gone.
British honeymooners Will and Ann Marie Husbands had booked the hotel in part because of its canals. They were debating whether they could brave the 90-degree-plus heat to take their planned gondola ride in the canal in front of the hotel, which was still flowing but provides a much shorter ride.
"It's one of the things that it's most famous for, isn't it?" Will said, still smarting a little from the disappointment.
A steady stream of tourists stopped by a ticket kiosk to ask about the waterways.
One couple said they had come to Las Vegas exclusively to ride a gondola in air-conditioned splendor.
The man behind the counter, whose job is to sell people on shows and activities outside the hotel, has been responding to inquiries with shock and telling tourists that he still sees water flowing through the hotel.
The gag didn't go over too well with a Frenchman who spoke limited English.
The nightshift kiosk clerk has been keeping a tally of people who ask about the canals. One night's list had 90 check marks.
Tourists who aren't staying at the hotel seem to have a better attitude about the surprise. Before heading to the Venetian's luxury shops, Patricia Giles of northern England joked to her traveling companion that the canals had sprung a leak.
Workers who labor in the canals at night hide their hoses, tools and big orange buckets under blue tarps beneath bridges during the day.
Las Vegas Sands, which owns the Venetian, is aware of the tourist grumblings. After all, it is Las Vegas, where adults are supposed to be able to regress to a boozy infancy, with every need and desire accommodated.
For property management, the repainting ties into another quintessential Las Vegas theme: the promise of perpetual renewal.
"There's a very specific sparkling blue color that we're trying to achieve," spokesman Keith Salwoski said. "It dulls over time. This is our opportunity to start fresh and have the canal be as bright as the day it opened."
The argument was lost on California resident John Rob as he discovered the dry waterways.
"Oh man," he said, hitting his wife's arm. "I wanted to go on a ride."