The “April Fish” Tradition

• While much of the world calls today April Fools’, the French have always done it with more style. They call it Poisson d’Avril — April Fish — and the tradition is exactly what it sounds like: children (and mischievous adults) sneak a paper fish onto an unsuspecting victim’s back.

When the trick is discovered, the prankster cries “Poisson d’avril!” Cats, of course, would never fall for such a thing. They’d smell the fish immediately.

Why a Fish?

The origin is delightfully murky or fishy, which feels appropriate for a holiday built on deception. The most cited theory traces back to 1564, when King Charles IX moved the New Year from April 1st to January 1st. Those who kept celebrating in April were mocked with fake gifts — often fish-themed, since the date fell during Lent when fish was the only acceptable protein on the table.

Another theory points to the fishing season itself: April’s waters were newly full, the fish plentiful and easily fooled into the net, a neat metaphor for the credulous. Astrologers will note that Pisces ends in late March, leaving its fishy energy still swimming through the first of April.

What the Vintage Postcards Tell Us

I’ve been collecting vintage Poisson d’Avril postcards for years, and recently found several new ones I couldn’t resist — including some featuring cats, which felt inevitable.

In the late 19th and early 20th centuries, exchanging elaborately illustrated postcards on April 1st was a genuine custom, far removed from the internet pranks we know today.

What strikes me most is how romantic many of these cards actually were. The fish wasn’t just a joke — it was a symbol of good luck, friendship, and in many cases, barely concealed affection.