The FDNY has a hot potato on its hands.

A city firefighter says he’s being ostracized by his fellow Bravest — because he decided to become a vegetarian.

Anthony Harper, 42, an eight-year department veteran, told The Post he decided to change his diet about two years ago — and began refusing to help pay for or share in the communal meals at his Brooklyn firehouse.

“It seemed that every single meal there was a meat dish. It was always chicken and red meat,” Harper said.

“It’s a culture where you eat what everybody else eats, and if it’s not what you are accustomed to — and you want to slim down and lose weight and won’t eat it — well, it leads to problems.”

He claims his own problems started when his colleagues started riding him about his dinner choices.

But he said the harassment grew to the point where he became a pariah who was regularly given dangerous assignments on the roofs of burning buildings and threatened with physical violence.

One fellow firefighter, he said, head-butted him during a petty dispute about looking at a roster. When he complained, he was reassigned from Ladder 146 in Greenpoint to the department’s headquarters in Downtown Brooklyn, he said.

He complained that despite being more physically fit than he’s been in years, he’s been left to vegetate. All he does now, he added, is push buttons on a computer to print out medical forms.

Fire officials denied his claims.

“The idea that Firefighter Harper has been in any way harassed or bothered because he’s a vegetarian is nonsense,” insisted FDNY spokesman Jim Long.

“Firehouses across the city have individuals who are vegetarians or who have special diets — i.e., food allergies, etc. — and they are accommodated all the time.”

Harper said he swore off meat for health reasons when his wife became pregnant and he was about to become a first-time dad.

“I was fat,’’ he said. “I realized that I needed to make some changes.”

So I gave up cigars and meat, and I lost 35 pounds. And now my blood work is like it was when I was in the Army, when I was 21 years old.”

Harper — who’s run in marathons since becoming thin — and his wife, Dakota, have a 2-year-old daughter, Sofia.

He said that before the vegetable viciousness began, he “never had an issue with discipline or anything.’’

He claims he was the only city firefighter written up for missing work because of Hurricane Sandy. He lives on Staten Island and said he had trouble getting to work.

An official said he was considered AWOL but could not confirm that other firefighters who missed work that day were excused.

Harper said he’s on the list for promotion to lieutenant. The department is expected to seek a hearing on his case, but he’s afraid it’ll be a sham and just provide an excuse to take away vacation days and, more important, deny his promotion.