Who hasn’t checked into a hotel and felt the crush of loneliness?

There’s just something about a rented room — the meticulously made bed with the crisp comforter, the little plastic sleeves covering the cups, the faint smell of bleach.

Once you check out, will the staff scramble to erase every trace of you, too?

For many of us, it all adds up to a kind of "lonely traveler syndrome." We’re just ships passing in the night, watching pay-per-view until the morning light.

Well, one hotel understands that existential void. A hotel near the airport in Brussels, Belgium, is hoping to fill your loneliness with a friend — a little fish, to be specific.

At the Hotel Charleroi Airport in Gosselies, you can rent a fish for just 3.5 euros per night, or about $4. The animal is expected to be returned by checkout in the same condition it was found, but possibly with a little extra glow on its cheeks for the time spent with a like-hearted soul.

“We started a few years ago,” hotel manager David Dillen tells the The Independent. “The idea was to surprise our guests, as we always try to do. It’s brilliant to see how people react to it. They smile, they take pictures to put on social media. We rent a few fish per week.”

At first blush, it’s an appropriate choice for an evening companion. Of all our animal companions, a fish in a bowl may come closest to approximating how the guest at a hotel near the airport might be feeling: disconnected, aimless, anonymous.

But maybe, despite the hotel’s gesture, having a fish around exacerbates that sense of loneliness. Sitting in a hotel room staring at a fish that stares back at you might put you in a darkly philosophical state.

Welcome to the Hotel Charleroi. You can check out any time you like. But this fish can never leave.

Closeup of fish eye When staring at a fish in a bowl, it's important to remember that the fish is staring back at you. (Photo: Kletr/Shutterstock)

Even if you don't start asking yourself deep questions, you might at least ask questions about the fish's overall well-being. After all, how happy can a fish be in a bowl — a bowl that is carted around the hotel?

It's those very concerns that have landed the hotel in a decidedly warmer bowl of water on social media, where critics say no animal should be available for hire.

So maybe, despite management’s best intentions, this idea isn’t a great one. Maybe, instead, a guest at an airport hotel could try more traditional means of escaping loneliness. Like leaving the room. And walking around a bit. Anything really, to escape the fish bowl.

Or at least, we could inquire at the front desk about an upgrade. Something with cuddlier, sunnier disposition?

Would you happen to have a bunny rabbit? Perhaps a corgi?

No sir. Just the fish.

It's a nice gesture, but it might just leave you longing for home.