Smokey the goldfish is a survivor.

For 21 months, the tiny goldfish lived in a pond covered in plastic and plywood, without food or sunlight. It was believed that Smokey had been removed from the pond after a fire on December 7, 2011, in Essex, U.K.

"Smokey's story exemplifies the remarkable adaptations fish have in their toolbox for getting through tough times,” Professor Matthew Gage, from the biology department at the University of East Anglia, told the BBC. “They keep themselves on trickle charge by living off internal fat and protein reserves laid down during times of plenty.”

Owner Jackie Broadley, 60, is happy to have Smokey back. “When I got the phone call to say there was a surviving fish from the old pond, I thought somebody was winding me up,” she told Metro UK. “It’s really nice to have Smokey, as it was a horrible experience for us to lose our house and have to re-home all our other fish.”

Builders found Smokey earlier this month while doing reconstruction work on the home. When they found the three-inch-long goldfish swimming in murky water, they gave him an appropriate-sounding name.

And for whatever reason, Smokey doesn’t appear to be affected by his time spent in the pond.

"Fish require oxygen in the water to breathe, so it's quite a surprise that Smokey has survived so long in a covered-over pond with no obvious source of aeration,” Katya Mira, from the Royal Society for the Prevention of Cruelty to Animals (RSPCA), said.

Gage says Smokey’s seemingly hostile environment probably saved him.

"It's quite likely that the lack of light helped Smokey here by shading the pond and keeping it cool,” Gage said. "The other possibility is Smokey was simply surviving by eating invertebrates that naturally colonize any garden pond, such as worms, insects and small snails."

Smokey wasn’t the only pet saved from the blaze. Two snakes from one of the houses were rescued during the 2011 fire, which forced 24 people to leave their homes.