It happened around 12:30 a.m. in the Lids Pike Bar on Germantown Avenue and 15th Street in the Tioga Nicetown section of the city.
Police say the fight started over a game of pool.
At one point a man pulled a gun and shot another man several times.
There's no word on the condition of the 32-year-old shooting victim.
A second man was injured during the fight.
Police arrested a third man and are questioning the bar's armed security guard.
