McDonald's Canada was not Lovin' It when they found out an Edmonton restaurant was serving up a cod burger called the Effing Filet O' Fish.

Woodshed Burgers received a cease-and-desist order from the burger giant on Wednesday.

The letter warned Woodshed to change the name of its fish burgers or risk a court battle over trademark infringement.

Getting served by the makers of the famed Filet-O-Fish came as a shock to Paul Shufelt, the owner and chef at Woodshed.

'I couldn't help but chuckle'

"As a small business owner, the first time you open a letter from a lawyer, you always get a little bit nervous. Like, 'Oh gosh, what have I done?'

"But as I started reading through it, I couldn't help but chuckle."

The letter — from a law firm representing McDonald's Corporation and McDonald's Restaurants of Canada — said the similarly named cod burgers were "likely to cause confusion amongst customers" and "diminish and dilute" the strength of McDonald's trademark.

In an emailed statement to CBC News, McDonald's said the company takes intellectual property rights "very seriously."

"Canadian trademark law requires a trademark owner to take steps to prevent the unauthorized use of its trademarks, regardless of who is using them, or risk losing the rights to those trademarks," the statement said.

McEffing Fish Fillet

Shufelt found it strange that such a large corporation would be concerned about his 49-seat restaurant.

When naming the burger, trademark issues never crossed his mind.

"Obviously McDonald's has sold a metric ton of Filet-O-Fish over the years and it's done well for them," Shufelt said in an interview with CBC Radio's Edmonton AM.

"It was never meant to be an insult. It was sort of meant to say, here's our take on the classic."

Instead of facing the fast food chain in court, Shufelt has changed the name of his cod burgers and acquired a trademark of his own.

"I do not have the wallet or the time or the energy to fight a giant like McDonald's,"Shufelt said.

"I'm sure they could easily bury me if they choose to but we're not going to roll over completely. After speaking with our lawyers, we decided it was best to change the name but we're trademarking the McEffing Fish Fillet."