It's unclear exactly what sparked the melee in Nashville ... but based on commentary from the guys in the fight, it seems a remark or two about a woman in the area set it all off.

You can see in video from the scene, bystanders tried to separate the guys before the fists started flying ... but ultimately the men were able to get a hold of each other and started to pound on one another.

For several moments, they traded blows ... but they were pulled away from one another. However, the two were able to reconvene the fight just seconds later.

Eventually, a right hand sent one of the men crashing to the ground ... mercifully ending the battle.

According to the Nashville Police Dept., no arrests were made.

"It looks like it had dissipated at the end of the video when an officer is seen," a police spokesperson said. "There were no calls."