Fontaine bought himself a pie and a drink.
They were leaving the dairy when a "suspicious looking" man wearing a balaclava walked in.
"I had put my pie and my drink into the car when the store owner chased this man out of the shop," he said.
Fontaine took off after the robber, along with another customer from the store.
"We both got him on to the ground and pinned him there while my sister was in the dairy helping out and calling the police."
The man put up a bit of a fight, he said, but he and his friend put him in his place.
"We just told him 'look, don't make more trouble for yourself. The more you fight the worse it's going to be'."
He said police took over when he and his helper happened to flag down an off-duty officer.
On Sunday, Senior Sergeant Kevin Stewart wanted to thank the "fairy hero" for saving the day.
"We want to give our pink fairy hero and his acquaintance a big pat on the back for preventing this offender from getting away," Stewart said.
A 42-year-old man has been charged with aggravated robbery and is set to appear in Hastings District Court today. He was treated for minor injuries.
Police are investigating the incident and would appreciate hearing from anyone who has any information.
Fontaine said he had been back to the dairy this morning to check in and have a chat with the owner.
He hoped the incident would make anyone else think twice before targeting the dairy.
And the young crime stopper's fellow pink fairies are thrilled with his efforts.
"My nieces were blown away," he said.
"They were like, uncle you're my hero - my pink fairy hero."
