Goldfish Memory Span: Do They Really Have a Short Memory? 

We all have that forgetful friend. The one we say has “the memory of a goldfish.”

But what if I told you that expression was not exactly fair to the goldfish? You may be surprised to learn that a typical goldfish (Carassius auratus) actually has an impressive memory span!

Goldfish swimming in an aquarium, shot sideways

Both research and anecdotal evidence indicate that these fish can remember details over time and can also be trained to perform and repeat tasks.

These actions simply would not be possible if they forgot everything after three seconds!

Read on for some amazing things goldfish can remember.


There have been a number of experiments done to assess the memory span of goldfish.

While none of the experiments indicate the upper limit of time that a goldfish can remember a task or a response, they show that goldfish memory is much longer than myth suggests.


Some of the experiments used the concept of classical conditioning, in which a neutral stimulus becomes associated with a conditioned response.

A study done in Israel used music to condition goldfish to associate the sound with food. When researchers played the sound, the fish would come to the food.

The study found that the fish remembered this association months after the experiment was complete, indicating that goldfish have a memory span of at least five months.


Other experiments involved the use of mazes and positive reinforcement with food to show that not only can goldfish memorize the path through a maze to get food, but they can also use the locations of objects outside of their enclosure to help them find the way.

The times the goldfish required to find the food decreased significantly as they “learned” their way through the maze.

Some of these studies went further to assess the length of time this memory was retained.

Researchers tested the ability of the goldfish to recall the path several months after being exposed to the maze.

In these cases, the goldfish could recall the path at least six months later, often with faster completion times than they achieved in training.

Physical Action

Researchers at Plymouth University conducted the third area of study. They first trained the goldfish to press a lever to get food.

Once training was complete, they set the lever to only function during a pre-set feeding time.

The goldfish not only learned to press the lever to receive food, but they also learned to only press it during the feeding time, otherwise ignoring the lever completely.

For the fish to learn this behavior, they would have to possess a greater memory capacity.

What Does This All Mean?

Oranda goldfish is searching for food a planted bottom of aquarium

Knowing that your goldfish has the ability to remember far beyond the three seconds of memory myth, how does that change the way you care for your fish?

In short, provide them with a suitably sized environment and ample stimuli for a happier, healthier goldfish.

Large Tank

Make sure your goldfish tank is the right size. Keeping goldfish in too small of an aquarium does not provide space for them to explore.

We recommend at least a 20-gallon (80 l) tank for an adult goldfish. Add on at least 10 gallons (40 l) for each additional fish (20 gallons for the larger varieties).

Stimulating Environment

Your goldfish will benefit from having things in their environment to explore.


Fantail goldfish is swimming close to the sandy bottom

To stimulate your goldfish’s natural foraging behavior, line your tank bottom with a soft sand.

Your fish will enjoy rooting around the tank bottom to find tidbits to eat. The benefit of sand over gravel is that it will not harm your goldfish if some is accidentally swallowed.


A group of oranda goldfish swimming in a planted aquarium with air stones

A goldfish’s natural environment includes ample plant life. Live plants in your goldfish tank not only help improve the quality of the water but they are also interesting to your goldfish and give them places to swim through.

Consider plants that grow to various heights in the water column, such as anubias, Amazon sword, and java fern.


Decorated goldfish aquarium

Similarly, decorations in the tank provide visual stimulation for your goldfish. Stone or artificial caves, driftwood, and rocks all create nooks for your fish to check out.

Rearranging the decorations every so often will create a “new environment” for your fish.


Goldfish are social creatures. While not specifically a schooling fish, they enjoy interaction with more of their own kind or another compatible species.

Always ensure that the tank mate you are choosing is a good match for your goldfish in terms of water parameters and personality.

Closing Thoughts

We hope you can see that goldfish deserve a reputation for their incredible memory ability. As an owner, we also hope that you see the value in providing the ultimate stimulating environment for your aquatic friend.

Now let’s hear from you! How have you noticed your goldfish’s ability to remember things?