It’s really not a fish tale, according to Metro. But it is a smell.

That stink that riders have been reporting in Metro stations is just a question of sewer gas, not fishy organic brake pads.

Last week, riders reported a smell likened to rotting fish emanating from the Gallery Place Metro station. On Friday evening, the smell had migrated to McPherson Square. It indeed smelled like fish stink.

The blog Unsuck DC Metro reported from a tipster that the smell came from organic brake pads the agency purchased then tried to get rid of, unsuccessfully.

But the smell has “nothing to do with organic brake pads,” Metro spokesman Dan Stessel told The Washington Examiner on Monday.

Instead, he said, the smell occurs when floor drains in the tunnels dry out, letting sewer gas escape. “The solution is adding water to the drains, which will require a track outage,” he said.