Goldfish memories last much longer than three seconds.

Saying someone has the memory of a goldfish is a derisive comment that implies they can only retain information for a few seconds — but this widespread belief is a common misconception, as goldfish don’t have poor memories at all. In fact, these popular pets can recall details for weeks, months, and even years.

Research has shown goldfish hold onto information for prolonged periods, especially if that knowledge is tied to receiving a tasty treat. In certain experiments, goldfish have learned which side of the tank they’re typically fed on and have been taught to press against a red paddle that rewards them with food instead of a blue-colored paddle that doesn’t. There’s even evidence of goldfish recognizing visual cues to navigate their surroundings, and they’re also able to discern between photos of frogs and turtles shown to them at varying three-dimensional angles. 

These and other tests were conducted over periods of weeks or more, proving goldfish can retain learned knowledge over time and dispelling the myth of their supposed three-second memory.