TORONTO – In downtown Toronto, you can sleep with the fishes – literally.

Lights out, huddled in a sleeping bag on the floor of an underwater tunnel with grim-faced sharks gliding above, the sleepover is one of the unique experiences offered by Ripley’s Aquarium of Canada, which is celebrating its first anniversary Oct. 16.

When the sun comes up, it’s a different scene. A moving walkway guides visitors through the underwater vista of the Dangerous Lagoon, oohing and ahhing over endangered species like the green sea turtles and massive green sawfish around them, cellphones cameras snapping away.

“I think they have a lovely layout and I really appreciate the walkway that makes people not get in the way,” said Ingrid Young, who’s from Buffalo, N.Y., but is working in Toronto. But some of the tanks with the biggest fish were too small, she said.

Kelly Smyth, 33, said she enjoyed seeing the underside of stingrays in the underwater walkthrough. Her sister Sarah, 29, said her 14-month-old son Corbin loved playing with the wheels in the central kids play area.

There are other unusual sights: sex-changing sergeant majors, a delicate leafy seadragon and a sour-faced giant grouper, which can weigh 400 kilograms and produce a thunderous sound by contracting a gas bladder that can be heard over long distances. Perfect for a pint-sized future Jacques Cousteau.

But the first thing visitors encounter are Canadian species, starting with the Great Lakes. They can move along to the knobby-shelled Puget Sound king crabs, or find themselves mesmerized by the gentle swaying motion of the tall kelp and finned inhabitants of the Pacific tank.

You can duck under a small tank and pop up in a bubble to see what’s going on or pose for an Instagram-ready photo op. Smaller children can crawl across a clear acrylic tube that runs through the middle of a different tank.

Information about the fish and other underwater organisms are provided on brightly lit screens, along with games and puzzles. There’s a scale where visitors can find out just how much they’d be worth as tuna. Turns out it amounts to a small fortune.

The aquarium’s massive water filtration system and tanks are on full display, with a mini version available for kids to learn about the mechanics of the system.

There are 50 exhibits, but over 100 “interactives,” said Peter Boyle, general manager of the 12,500 square-metre structure.

“What sets out aquarium apart from others is we’re real and we’re fun,” he said. “It’s real fish in real environments we’ve created, but we do it in a fun way.”

There are shallow pools where visitors can pet prickly crabs or small sharks. Admission includes live shows five times a day where divers feed tropical fish or smiley-faced rays. The brightly coloured swimmers that inhabit the Rainbow Reef tank are also a crowd-pleaser, where kids can spot the real-life versions of Nemo and Dory.

But the top favourite is the jellies, Boyle said. People post more photos of themselves with the neon-hued invertibrates than anything else.

“Social media now is driving so much,” he said.

“I saw a group of 20-something people there and they were on a corporate outing and they were raving about the jellyfish.”

Young and Stephen Wilson, who comes from New Zealand but currently lives in England, said they were impressed with the variety of fish on display. Their only complaint was the ticket price – $29.98 per adult.

“Much too expensive,” she said. “But it’s right downtown, so you kind of expect it to be too pricey.”

The aquarium has exceeded its initial projection of two million visitors in the first year, Boyle said, but wouldn’t reveal the exact figure. Visitors are also staying longer than they expected, about two-and-a-half hours.

And it’s not just for kids. Boyle said they were pleasantly surprised to see many adults coming to the aquarium as a date night destination, particularly on Wednesday and Thursday nights.

They’ve created a monthly jazz night, where adults can nibble on food, sip drinks and enjoy a live jazz band as they move through the winding path. It’s increased their evening attendance by 50 per cent.

“We have a great facility,” he said. “It’s well themed and we just want to try different things with it.”