"Hotarubi" (蛍火) ("Firefly-fire") is Rythem's twelfth single which was released on February 28, 2007, under Sony Music Entertainment Japan label.

The title track was used as the ending theme for TV Tokyo's show FIGHTENSION☆SCHOOL.

This single reached the #36 spot in the Oricon weekly charts.

The item's stock number is AICL-1847.

This 2000s Japanese single–related article is a stub.