However small and insignificant-looking a goldfish may look, there is just no way it has a mere three-second memory. Just think about the implications of having a three second memory. For starters, how would the goldfish know what kind of food it is supposed to eat, or where it is supposed to sleep? In the vicious, cut-throat world that is the animal kingdom, there is just no way an animal with a three-second memory could pull through millions of years of evolution unscathed.
This myth is strange because no one is quite sure how it originated. Perhaps some presumptuous biologist decided that the memory of the fish must match the size of the fish itself.
In any case, many experiments have been conducted that unequivocally prove that goldfish have memories considerably longer than three seconds. In controlled environments, scientists managed to train goldfish to respond to various stimuli such as colour and music. Not only did the fish learn quickly, but they also showed the same responses to the stimuli several months later. Researchers also managed to train the fish to push levers and play soccer, among other things. Further, research has shown that the goldfish can recognize human faces. They tend to be more active around people who they known and recognize, especially the person who feeds them.
While the exact length of goldfish memory remains unknown, it is clear that it is more than three seconds.