Forget turndowns, room service, or complimentary pillow mints. A hotel in Belgium has come up with a unique added extra on a different scale: rent a fish for an evening.

The manager of the Van der Valk Hotel Charleroi, about 70 kilometres south of Brussels (44 miles), said the idea to lend out the establishment’s three goldfish came to him a few years back when he noticed guests getting bored at the reception desk.

“I wanted to make things more interesting, to make people laugh,” David Dillen told AFP.

He decided to offer guests the chance to keep one of the establishment’s goldfish — currently a trio named Nemo, Heineken and Prince Charles — in their room.

Since then, several guests have taken him up on the offer to rent a fish for 3.5 euros ($4) a night (fishbowl included), with satisfied customers carping on about the deal on Facebook and Twitter.

“Two or three years ago, an Australian wheelchair tennis player couldn’t sleep so he decided to film the fish and post the video on social media,” Dillen said.

An image by a Dutch tourist posted online by her friend racked up 30,000 likes on Twitter in a matter of days this month.

“We now have three types of guests: those who post online photos of the fish in their room, businessmen who can’t wait to send their receipt to their boss, and families to whom we lend the fish for free,” said Dillen.

But the scheme doesn’t always go swimmingly.

“A three-year-old Dutch girl kidnapped one of our fish,” Dillen said. “Her father, who found it in the car on the Belgian-Dutch border, immediately called us. The hotel offered it to them”.