One girl was arrested and another was taken to the hospital after a fight at Carson High School early Tuesday morning.
Shortly after classes began, a fight broke out between two freshman girls in the north hallway, school officials said.
The fight was caught on video surveillance cameras, showing one girl knocking the other to the ground, then kicking her in the head.
Principal Glen Adair said the altercation lasted about 10 seconds, and paramedics were called because the girl was bleeding from a head wound.
Adair said no further injuries were found on the girl at Carson-Tahoe Hospital other than swelling around her eye.
The attacker was arrested on battery charges. The girls' names were not released because of their ages.
"If you get into a fight at Carson High School, you're arrested," Adair said.
Adair said the high school has seen few fights this year, with the majority of them between girls and stemming from problems with boys.
"Generally, they're getting after each other for stupid reasons," he said. "This one was no different. Why in the world would you fight over a boy?"
He said he was also bothered by other students' reaction to the fight.
"A bunch of kids saw it, and nobody stepped in to help," he said. "I find that just as disturbing as the fight."