You've surely heard the myth of the goldfish's three-second memory. But is it true that these animals forget everything almost instantly?
No. Scientists actually debunked this myth a while ago.
Back in 2009, Israeli scientists conducted an experiment to determine how long fish could remember things. The scientists taught fish in captivity to associate a certain sound with feeding time. The teaching process took one month. After that, the scientists released the fish back into the wild.
Five months after releasing the fish, the scientists returned to the area where they had been released. They repeated the "feeding time" sound, and the fish returned. They remember the sound after a whole five months!
But that study didn't specify the type of fish. Could goldfish memory be different?
The myth usually specifies that it's goldfish that have this extremely short memory. Is there any evidence that goldfish, the fish we typically keep as pets, have a different memory span than fish found in the wild?
Well, no. In 2008, a 15-year-old Australian boy named Rory decided to conduct his own experiment to determine how long his pet goldfish could remember things.
First, he taught them to associate food with a red LEGO. Then he let a week go by without putting the LEGO in the tank. When Rory reintroduced the LEGO, the fish quickly swam toward it, expecting food.
"MythBusters" on the Case
"MythBusters" also tested the myth of the goldfish's three-second memory. Adam Savage and Jamie Hyneman constructed mazes inside fish tanks and attempted to teach their goldfish to swim through the mazes in order to get food.
While Savage's attempt failed miserably, Hyneman taught his fish to complete the maze in only 30 seconds. The fact that the fish remembered how to go through the maze day after day and improved their time shows that they can, indeed, remember things for much longer than three seconds.
Where did the myth come from?
Pretty much everyone who knows this myth is false agrees it was invented to make humans not feel guilty about keeping goldfish in small bowls.
But fish need mental stimulation to stay happy, just like all other animals. Pet fish are happiest in large tanks with lots of interesting features. They'll be even happier if you rearrange the tank regularly.