What are the consequences of high school students' group fighting? Will they go to jail?

Senior one students are generally under eighteen, so they won't go to prison. Specific reference:

A person who has reached the age of 16 commits a crime and shall bear criminal responsibility.

A person who has reached the age of 14 and is under the age of 18 commits a crime and should be given a lighter or mitigated punishment.

The principal offender shall be punished according to all the crimes he participated in, organized or directed.