Shawn McKenzie, 24, died in hospital on Monday after an altercation with a fellow inmate the day before.
Both men were brought to hospital with injuries on Sunday, but the other inmate, 41, has since returned to the Collins Bay Institution.
McKenzie was convicted of first-degree murder in February 2009, for an unprovoked attack he carried out at age 17.
On Sept. 21, 2006, McKenzie approached Michael Oatway, 23, on an Ottawa bus and demanded he hand over his iPod.
Oatway refused to do so and McKenzie attacked him with a knife, stabbing him multiple times.
Two years later McKenzie was sentenced as an adult to life in prison with chance of parole after 10 years.
Anthony Doob, an expert on criminology and youth justice, said McKenzie's sentence was one of a few "rare" cases in Canada. Even rarer still is to die in a prison fight, said the University of Toronto professor.
He said from 2001 to 2011, there were 29 homicides in Canadian prisons.
At the time of McKenzie's sentencing, the judge said Oatway's murder was a notorious day in Ottawa's history and lifted the publication ban that normally prevents a young offender's name from being released publicly.
An adult sentence put McKenzie, who had no criminal record before killing Oatway, under the jurisdiction of the Correctional Service of Canada.
"Unless you've done something really terrible you don't go to a penitentiary the first time you go to prison," Doob said. "(Federal prisoners) may come in at a young age but they are there for a long time."
An autopsy on McKenzie is being scheduled and the penitentiary squad, under the Ontario provincial police, are continuing their investigation.
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