Fred is one of Ron's trouble-making brothers.

Fred, aswell as 7 other players, plays for the Gryffindor Quidditch Team.
His position is Beater aswell as his brother George. The Beaters have to slog the balls called "The Bludgers" from hitting anyone of the players. They do this by smacking the balls towards the other teams players with a club.

At Hogwarts, he and George have a whole file to themselves for all the rules they've broken. Their Mother gets a lot of Owl's from Hogwarts because of their rule breaking and mistakes. They both want to open a Joke Shop when they leave Hogwart's and they most likely will because In the end of The Goblet of Fire, Harry gave them the One Thousand Galleon's he won from the Triwizard. 

In the Goblet of Fire, they try to trick the Goblet of Fire in believing they were over 17 with a ageing potion, but it didn't work and they got beards from it. They made a bet with Ludo Bagman on the Quidditch World Cup match that Krum would get the Snitch but Bulgaria wouldn't win, that happened but Bagman gave them Leprechaun Gold, which disappeared after a while.