The pushing and shoving began inside the courtroom hallway Friday morning and then spilled outside.
Two court officers were injured in the melee and taken to the hospital.
It happened during the arraignment of Pedro Merchant.
The 20-year-old is accused of shooting 17-year-old Dante Quinones to death on a street in Hempstead last week.
Both families were in court Friday and apparently tempers flared.
Newsday reports that shortly after a judge remanded the suspect without bail, an outburst of support for him sparked the fighting. Two of those arrested also had to go to the hospital because they were injured during the brawl.
The six suspects have been charged with criminal contempt and riot.