Dramatic video shows the chaos where up to 30 people fought during a one-day South Pacific cruise on the "Carnival Legend."
Security guards stepped in, pinning some of the guests to the ground and kicking two people. It was just one of several fights on board.
Some people with children reportedly locked themselves inside their cabins.
Carnival blames a large family for starting the fight. It said it cooperated fully with authorities in Australia to remove the family from the ship.
The company apologized to passengers and offered them 25 percent off of their next trip.