Like most brilliant ideas, this one came about over beers: a goldfish rental service for lonely hotel guests.

Incredibly the booze-infused concept quickly became a reality and has since turned Hotel Charleroi Airport – an otherwise ordinary inn near Charleroi, Belgium – into an unlikely internet sensation.

Social media posts of the goldfish, which can be rented for €3.50 (£3.20) per night, now occupy one of the weirder corners of the web and have proven particularly popular with business travellers.

“They like to go back to the office with an expenses claim for goldfish rental,” said David Dillen, the hotel manager, who decided to buy the fish while he was propping up the bar at the family-run hotel.

My friend is staying in a hotel in Belgium. They've offered her the option of renting a fish for the night, in case she's lonely. #noshit pic.twitter.com/DG74iRSfhY — Michelle Cooke (@Mich_Cooke) September 2, 2017

“I was having a beer with my cousin and we saw some people waiting to check in,” he told Telegraph Travel. “The queue was quite long so I decided to go out and buy some fish [as entertainment].”

The fish were initially intended to keep guests entertained while they waited to check in, but the critters became so popular that the hotel started renting them to lonely lodgers.

The fish spend most of their time swimming around in a bowl at reception, but when guests need some companionship they are sent to receptacles in their appointed room.

The hotel has taken some flak from critics, who have questioned the size of the goldfish bowl and the ethics of renting the creatures to guests, but Dillen claims they are regularly transferred to a big fish tank in the housekeeping department where they have access to shelter and plants.