My father, who is a very curious, bookish person, recently read a book that interested him greatly: Joseph Torigian’s biography, The Party’s Interests Come First: The Life of Xi Zhongxun, Father of Xi Jin Ping.

Xi Jin Ping, of course, is the extraordinarily powerful and influential president of China today.

My father shared many interesting insights and facts from the book, and also, because he knows I love a great teaching story, he told me a story that appears in the book, about the sardines and the catfish.

I loved this story, so I looked it up, and apparently it’s a well-known teaching story. Here’s my version.

Once upon a time, people who lived far from the sea learned about sardines, and they all wanted to eat this tasty fish.

But the sellers of the sardines faced a problem: How could they transport the sardines across the countryside and keep them tasting fresh?

Someone tried shipping the fish by railway in huge water tanks, but the sardines became lethargic and some even died along the journey, so when they arrived, they were no longer fit for sale.

Then someone thought about catfish, a predator of sardines.

After they placed sardines in the water tanks, they added a catfish. To avoid the catfish, the sardines had to stay active and alert, so when they arrived at the market, they were in a fresh state.

The lesson is that  in order to stay in best form, we need to stay alert and active.

Because of this story, people use the phrase “catfish effect” to invoke the idea that having a strong competitor can cause a person or an organization to work harder and to stay engaged. People also use the phrase “catfish management” to convey the idea that when an energetic, highly motivated person is introduced into a team, other team members start to work harder.

Now, as it turns out, this story is apocryphal. Catfish and sardines don’t actually exist in the same environments. Also, putting predator and prey together in a tank would mean that the prey would get eaten or die from stress, and even if they didn’t get eaten or die, the stress would make them taste worse, not better. No only that, no one has ever transported live sardines in tanks by rail this way.

So this teaching story isn’t historically accurate—but it’s a popular story, because it makes a useful point. Being in an environment where we need to show hustle and energy can be better for us than being in quiet, stagnant surroundings.

Sometimes a teaching story has such a great lesson that it doesn’t even matter if it’s not true.