“Goldfish have a three-second memory”

The widely circulated idea that a goldfish's memory lasts only three seconds is a persistent misconception with no basis in scientific fact. The exact origin of this myth is unclear, but experts suggest it likely emerged from a combination of a general lack of understanding about fish intelligence and perhaps a subconscious desire by pet owners to justify keeping these animals in small, often unstimulating, environments. If a goldfish quickly forgot its surroundings, the thinking went, it wouldn't mind a tiny bowl.

However, scientific research has consistently busted this myth, demonstrating that goldfish possess robust long-term memories that can span months, and even years. As early as the 1950s and 60s, studies revealed their capacity for learning and retention. For instance, goldfish have been trained to push levers for food, navigate complex mazes, and recognize specific feeding times and locations, retaining these skills for extended periods. In one remarkable experiment, goldfish learned to associate a particular sound with feeding and, even after being released into the wild, returned to their original feeding spot five months later upon hearing the sound again.

People commonly believe the three-second memory myth partly because fish lack a hippocampus, the brain structure associated with explicit memory in mammals. This led to the incorrect assumption that fish couldn't form memories at all. However, fish brains have other regions, such as the pallium, that serve similar memory-forming functions. The perception of goldfish swimming aimlessly in circles in a small tank also contributes to the myth, as it gives the impression of a creature without awareness or memory. In reality, these aquatic animals are far more intelligent and capable of complex cognitive abilities than they are often given credit for.