Why don't you pick on someone your own size?

There couldn't have been a more fitting expression to describe a man who was caught brawling security footage at a Rockingham health centre on Saturday.

Not only was his opponent exactly the same height as him, he was also the same weight and had the same fighting skills - because it was his own reflection.

The man was captured by CCTV at the Rockingham Maternity and Family Practice, walking down a corridor, spotting what he thought was another man in the windows and starting to throw fists at the perceived opponent.

Practice assistant manager Jessica Neal said when staff returned to work on the following Monday, they found three windows smashed.

"We looked through the CCTV and saw this guy, talking to himself and fighting his reflection," she said.

"He then turned around and obviously saw another reflection of himself. I think he then thought there was a whole gang, so he took off."

She said when tradesmen came to fix the damage they told her windows at Rockingham Hospital and another medical centre in the town had also been smashed, albeit on different days.

"It's a bit of coincidence," she said.

Staff at the practice had reported the damage to Rockingham police, who have been contacted for comment.