April Fools’ Day is made for silliness, and silliness is something the Portland-based Illustration Institute takes very seriously.

That means Thursday could be a lot of fun. Scott Nash, the institute’s executive director, hopes to turn April Fools’ Day into a day of celebration for illustrators worldwide based on the French tradition of Poisson d’Avril dating to 1582, when the French calendar shifted its new year to Jan. 1. Those who celebrated the new year the old way, on April 1, were pranked by having a paper fish placed on their back to indicate they were gullible, or easily hooked. They were called “poisson d’Avril,” or April fish.

The Illustration Institute is promoting April Fools’ Day as an opportunity for illustrators to flood social media with images of original silly fish and tag their friends. “We can’t be together so we can’t physically stick the fish on people’s backs, but we hope artists all over the world will create fish and tag their friends on social media,” Nash said. He’s asking artists to post their creations to Facebook and Instagram.

“We believe certain holidays are made for illustration, especially non-secular ones,” he said. “April Fools’ has been under-served as far as illustration goes. Our mission is to create awareness of illustration, so this is perfect sort of fun for us, creating and playing together. We will be pushing a lot of fish out there on social media on April 1.”

Among the illustrators who have committed are Rolling Stone magazine cover illustrator Anita Kunz, picture book artist Juana Medina and local illustrator and Maine College of Art educator Mary Anne Lloyd.

To see some of the early illustrations, visit group’s Facebook page.