Sci-Fi Short Story Futuristic Setting Heist

I read this in an anthology around 9-10th grade (late 1990's - early 2000's). I remember that it was a science fiction feel, a futuristic setting, and it was about some sort of heist. My first instinct was an art heist, but that might not be it. It is told from a detective point of view (omniscient author though), where the detective is retelling the story of the heist to another person. At the end it is revealed that the man he is talking to is the culprit, and the detective knows it the whole time but lets him try to play it cool. They were talking while waiting in line for some from of travel. The feel of the story is similar to Ray Bradbury, H.G. Wells, Jules Verne, or the like. You know, someone who wrote before the advances of modern scientific technology. I've tried looking at those authors, but short of rereading everything they wrote, I haven't had much luck. Although...here's a great excuse for a read-a-thon!

At some point I think one character says to another "You seem to be rather green about the gills."

If this rings a bell at all I'd appreciate any tips...otherwise, you'll find me buried in books at Barnes and Noble. :)

I think this is "Trouble with Time" by Arthur C. Clarke, originally published in 1960 with a different title. The detective is talking to an art dealer while waiting for a ship to take them back to Earth from Mars. Someone recently tried to steal a mysterious statue called the Siren Goddess from a Martian museum. They caught the thief but think he already had a buyer lined up, but there's no proof about the buyer's identity. It's not outright stated but it's implied that the art dealer is the buyer, and the detective knows this. The line about being green occurs in the last couple of paragraphs.

That is it! Thank you so much...I would have read a long time before getting around to Clarke.

Happy to help! I read Clarke's Collected Stories over the summer so it was fresh in my memory, but I'm sure it's been anthologized elsewhere too.