The scuffle broke out at about 2:30 p.m. during the prisoner's walking hour in an outer courtyard of the federal Sainte-Anne-des-Plaines facility, where Boucher is held in a special unit.
Corrections Canada confirmed Saturday night that four inmmates were involved.
In a press release, Corrections Canada said that the two "abused" inmates have been treated and the two assailants are currently in isolation. Corrections Canada has not named the inmates involved.
QMI Agency has learned that former Hells Angel Boucher was one of the injured inmates. He was not seriously injured in the brawl and his life is not in danger.
Witnesses told TVA News that the guards in a watchtower saw the attack and were able to alert their colleagues on the ground, who moved quickly to separate the inmates.
One witness said it's possible that Boucher would have been in very bad shape after the scuffle if the guards hadn't intervened.
The Correctional Service of Canada is investigating the scuffle.
Quebec provincial police, the Surete du Quebec, were also notified.
Claude Ross, spokesman for the force, confirmed that there were two victims in the scuffle and that two suspects have been arrested.
"They were found by the investigators in the West region," he said in French, adding that neither of the injured agreed to be transported to hospital for treatment.
"The fact that they refused to be taken to the hospital suggests that their injuries were not too serious," he said.
Boucher, former boss of elite Hells Angels chapter the Nomads, is serving a life sentence for orchestrating the killing of two prison guards.
Boucher is being held in the special handling unit of the federal Sainte-Anne-des-Plaines penitentiary near Montreal. It's not the first time Boucher was attacked - he was the victim of a jailhouse ambush when he was assaulted with a homemade knife in 2002.