According to the goldfish memory myth, fish can remember just the past three seconds. Apparently, this is why goldfish can repeatedly swim around their bowls while thinking that they see something new in each circuit.
Like many other myths, this one is dead in the water.
Fish aren't forgetful little creatures that function as nothing more than another rung in the food chain. They can remember details for months, even years. Some fish species can successfully navigate mazes and use tools. Even the seemingly lowly goldfish have demonstrated that they can learn from training.
So what fish can exhibit these surprising and amazing capabilities?
Like goldfish, guppies are quite popular as pets. It may be easy to dismiss them and their capabilities, since guppies have an essentially ornamental role in home aquariums. However, just this year, scientists discovered that guppies have considerable navigation skills. Guppies were able to successfully navigate a maze in the study's experiment. It's not just that, though. The guppies also improved their speed and made fewer errors over the five-day course of the study.
Navigational skills may have evolved in guppies as an adaptation tool in their natural habitat. Guppies naturally come from streams, where there are a lot of obstacles to navigate through.
Guppies and other fish species have better spatial awareness than humans and other terrestrial animals. Fish have 3D spatial awareness, while humans struggle with the vertical dimension. Of course, fish need to have the ability to track depth and we humans don't, but it's still a nifty capability that we don't have.
Scientists often consider tool use as a sign of advanced cognition in animals. Many terrestrial and marine animals like primates and sea otters exhibit the ability to use tools. The archerfish, in particular, has an undeniably formidable set of skills.
The archerfish typically feeds on land insects. So how does the archerfish go about catching its prey? By using water as a tool, of course.
The archerfish positions itself near the surface of the water and selects its target. It then squirts a jet of water from its mouth at the unsuspecting insect. The jet of water dislodges the insect from its perch, and the insect then falls into the water and into the jaws of the archerfish.
It's not as simple as selecting a target and firing, though. The archerfish can also adjust the hydrodynamics of their water jets to account for the distance of the target.
We have to wonder why the goldfish memory myth has persisted for so long. After all, there's a 23-year-old study that found that goldfish can be trained to perform a specific action for a reward. If that study were a person, it would be working a minimum wage job by now.
Fish also have pretty sophisticated cognitive abilities. For example, the crimson-spotted rainbowfish can remember details of its escape route away from danger for about 11 months. That's definitely way longer than three seconds, and these rainbow fish sure aren't swimming in circles.
Humans have had a pretty dim view of fish. Perhaps the myth of the goldfish memory held on for so long because it's easier to believe. After all, it's difficult to imagine or visualize how fish must behave since they're so different from humans. Characters like Dory from Finding Nemo probably don't help the way we think of fish as well. Now that we know better, though, maybe we can look at fish more charitably.
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