Shocking footage shows a knife-wielding man in a brawl at the Dockle Farmhouse in Stratton.
Violence erupted at the pub on Friday night and videos of the incident have been widely shared on social media.
One video shows people screaming and shouting while others were thrown over the fence.
Another witness captured the moment when several men were punching and kicking each other. A knife-wielding man can be seen lunging towards the group.
In other footage, a young man with bloodied face was seen punching another man before leaving the scene.
Wetherspoon spokesman Eddie Gershon told the Adver that a group of males was walking along the pavement trying to work out how to get into the pub without queuing to get in.
He said the group got involved in verbal abuse with another group of men who were sat in the beer garden and is believed to be known to them.
Police are now looking for witnesses after an 18-year-old man suffered a head injury during the fight.
Anyone with information should call 101.