One of two pacific white-sided dolphins at the Vancouver Aquarium is recovering after what's being called a “breakthrough” surgery.

The 21-year-old dolphin, Hana, was fine all day Sunday, but Monday morning was not eating or engaging with trainers. After that, things turned for the worse.

Dr. Martin Haulena, the aquarium's head veterinarian, ran some tests and found Hana had a gastric condition that can be both rapid and life-threatening. She continued to get worse, so Haulena flew in experts from around the world to prepare for a milestone procedure.

"Four or five years ago we would have had absolutely no anesthetic or surgical options for this animal and that's how far we've come,” he said.

This is a first; no dolphin has ever been put under general anesthetic before. Haulena said the success of this surgery could change the course of future medical treatments for animals.

“It’s an incredibly inspirational event to see. We had 40 people joining hands and jumping in there and sharing their expertise,” he said.

But as for Hana, she remains in critical condition.

“Her demeanor is quite weak; she’s not able to swim on her own. So, that’s the next thing, I want to see her regain her energy.”

Haulena said the next 24 to 48 hours are critical and Hana is being watched around the clock.