'Mob Wives' Star Arrested Over Street Brawl ... Caught on Tape!

"Mob Wives" star Renee Graziano's 17-year-old son AJ Pagan -- also on the reality show -- was arrested Wednesday for his involvement in a massive street brawl ... but he insists he's innocent ... and there's video to prove it.

The rumble went down weeks ago -- AJ's rep tells TMZ, AJ and his girlfriend were driving around Staten Island and noticed two girls beating the crap out of each other on the street ... so they stopped to break it up.

The fight exploded -- involving multiple more people -- and we're told AJ jumped into action ... pulling one of the girls out of the melee. The fight eventually dissipated. No cops were called. And that was that.

Everything seemed hunky-dory until this Wednesday -- when we're told cops showed up at AJ's Staten Island home and arrested him for allegedly hitting one of the girls involved in the fight.

But AJ's rep insists AJ never hit anyone -- and video footage of the fight (above) proves it ... showing AJ pulling one of the girls away from the fight.

According to AJ's rep, the girl accusing him is just out to exploit the reality star because of his "Mob Wives" fame.