As MPs debated the potential reform, Gianluca Buonanno, from the anti-immigrant Northern League, pulled a sea bass from under his bench and started brandishing it around.
“When I heard about this debate, I thought it was an April Fools' joke,” he said.
He went on to say that , by debating whether to allow these immigrants to live legally in Italy, the government was neglecting the country’s pensioners, who, in order to get by, eat “anchovies and sardines”.
“This is for the House Speaker, who eats sea bass, while being moralistic about others, our pensioners and our unemployed.”
The scene was caught on camera.
Watch the video:
He was eventually ejected by Deputy House Speaker Luigi Di Maio after failed attempts to get him to stop waving the fish.
April Fools' Day is traditionally known as 'April Fish' in Italy, France, Belgium and French-speaking parts of Switzerland.
This is the latest stunt Buonanno has pulled in parliament in recent months. In January, he smeared his face with black greasepaint as he advised Italians to “become a bit darker” if they wanted to be treated as well as black immigrants supposedly are.
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Meanwhile, in September last year he provoked two openly gay MPs with a fennel bulb, or finocchio, which is the Italian slang for 'faggot'). The incident happened during a debate about the Italian pasta company Barilla, after its CEO sparked controversy for saying that the company would never feature gay people in its adverts.
The Northern League co-sponsored the law making illegal immigration a crime during the reign of ex-premier Silvio Berlusconi.