This is a fish story about the one that got away.

The world record musky didn’t wriggle free from an angler. Its photo disappeared from a frame screwed to the wall above a toilet in the men’s room at the Nite Owl Drive In.

A thief pried open the backing of the frame and took off with the 8-by-10-inch photo sometime Tuesday.

As crimes go, this one is very Wisconsin, where we love our fishin’ and huntin’ so much that this picture of a massive muskellunge proved irresistible to the lowlife who ran away with it. It was a crappie thing to do, for sure.

“They need it more than I do apparently. Whaddya gonna do?” Nite Owl owner Chris Roepke sighed when I visited the scene of the crime.

He’s the third generation to run the popular burger and ice cream place, which opened in 1948 and is across the street from the airport at 830 E. Layton Ave. Despite the name, it’s open only during the day.

The Nite Owl decorating style is nostalgia in frames that cover most of the wall space. There’s an autographed Eddie Mathews photo. Over there is a Frankie Avalon concert poster for a Milwaukee Arena show in 1960. One of my favorites is a publicity pic that “Jeopardy!” host Alex Trebek sent after Chris’ dad John wrote to him to say they shared the same birthday.

And then there was the black-and-white musky photo in a frame that also features a thermometer and a card that says: “Weight 69 lbs. 11 oz. Girth 31¼…