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Goldfish Memory Span: How Long Is It? Facts & FAQ

Lindsey Stanton Profile Picture

By Lindsey Stanton

lionhead goldfish swimming

Has anyone ever insultingly told you that you have the memory of a goldfish? I hope you thanked them for the compliment. See: There’s this silly notion floating around that goldfish are creatures of very little brain power—they don’t ever get bored because every three seconds they forget everything and they aren’t really capable of intelligent behavior.

Nothing could be further from the truth! And today we are going to show you the scientific proof that goldfish are smarter than what we’ve been told! Keep reading to get the scoop.

Do Goldfish Have Three Second Memories?

Celestial Eye Goldfish
Image Credit: Dan Olsen, Shutterstock

The short answer: No, goldfish don’t have a three-second memory span. In fact, they can likely remember things for several months, if not more.

If you’ve ever noticed your goldfish waiting for you to feed them at a specific time of day to check the same spots for leftover food, it should seem evident that they’ve recalled things from previous days.

Although it doesn’t relate to goldfish alone, modern science shows us that fish are much cleverer than people once believed. They have complex social structures, the ability to learn, and some species can even use tools.

Where Did the Myth Come From?

Image Credit: Petrychenko Anton, Shutterstock

It’s not clear exactly where the myth that goldfish memory is only 3 seconds came from or why it’s so widely perpetuated. However, it was likely designed to make people feel better about keeping them in small bowls with little to occupy them.

If you know that goldfish are intelligent, thinking creatures, then keeping them in a tiny tank with no form of mental stimulation is cruel. But, if you believe they have a memory span of three seconds, it doesn’t seem like a big deal, because they don’t even remember what happened four seconds ago.

So, what should you do with the knowledge that they can remember things for months? Get them a decently-sized tank with a range of ornaments and hidey holes, and perhaps some live plants to swim around in.

Goldfish Memory: What Are the Facts?

Image Credit: JuanCarlosPalauDiaz, Pixabay

We know for sure that goldfish don’t have three-second memories, but how? As well as observation and common sense, a range of scientific studies supports it.

Researchers at Plymouth University in the UK taught goldfish to request food by pushing a lever. They then changed things up by only releasing food when they first pressed the lever at certain times of the day.

Amazingly, these fish not only knew that pushing the lever would get them food, but successfully recalled what times of day they’d receive the food in exchange for pressing the lever, showing that goldfish can not only remember things, but they have a good sense of time, too.

Scientists at an Israeli university taught fish to associate a piece of classical music with food. Five months after the end of an initial one-month training period, they still came swimming over, looking for food, when they heard that piece of music being played.

Although it might not stand up to rigorous scientific standards, Jamie Hyneman, on the Discovery show Mythbusters, trained goldfish to swim through a simple maze, indicating that these fish could both learn and remember—no three-second goldfish memory here.

These are just a handful of the studies and experiments that show they can remember for far longer than 3 seconds. Although there’s no definitive answer to exactly how long they can retain information, it’s likely to be at least four or five months, if not indefinitely.

These studies retested the fish after a set amount of time to see if they could still remember but didn’t keep testing to see when they forgot. It’s entirely possible that goldfish can retain important information for years. Possibly even for their whole lives.

So, What Does This Mean for Goldfish?

As we touched on above, the fact that goldfish have longer memories than many people believe means that keeping them in unstimulating environments is cruel. You should provide them with as large a tank as you can, and certainly never keep them in a bowl.

Not only are bowls too small, but they also distort the way the world looks outside the bowl for your fish.

Based on the fact that goldfish may well remember things for years and are probably more intelligent than you give them credit for, try to provide them with a stimulating home environment. Give them plants or caves to hide in and explore, a suitable substrate to forage in, and change up the layout of their tank now and again, to keep things interesting.

It’s also true that goldfish are social creatures, so we’d recommend keeping at least two together—just make sure you get them a large enough tank. If kept alone, they can exhibit signs of depression, and in some countries, it’s even illegal to keep a single goldfish, due to animal welfare laws.

If you're new to the world of goldfish or are an experienced goldfish keeper that loves to learn more, we recommend you check out our best-selling book, The Truth About Goldfish, on Amazon.

From diagnosing illnesses and providing correct treatments to ensuring your goldies are happy with their setup and your maintenance, this book brings our blog to life in color and will help you to be the best goldfishkeeper you can be. 

Image Credit: kaori, Pixabay

Researching into Goldfish Memory Spans

A researcher offers his opinion regarding the stereotype:

“A lot of people have the image of a goldfish with a three-second memory – and that’s not the case at all. There is a lot of evidence now that fish are no dumber than birds or many mammals – and in many cases they are just as intelligent. They can learn their way around mazes, they can learn to recognise other fish, and they can remember which individuals are better competitors.” – Dr. Mike Webster

This is backed up by the facts. Take, for example, a 15 year old student named Rory from Australia who did a simple experiment to test goldfish memory capabilities.

“I decided to get a bit of red Lego and just feed them next to that. Every day I’d put it in and sprinkle food around it. At first they were a bit scared of it, a bit wary, but by the end of the three weeks, they were actually almost coming before I put the food in.” Rory told ABC News

The boy then waited nearly a week before putting the red Lego back in again.

“They remembered perfectly well. They actually had a time faster than the average of the three feeds before I left.”

This proved that the training not only stuck with the goldfish, but they could call it to mind at a later date – far beyond three seconds. But we’re getting started: Take, for instance, the findings of studies at Plymouth University that show how goldfish remembered things for 3 months and can even tell time! Their fish needed to nudge a lever in order to get food.

The researchers then made it so the lever only worked for one hour every day. Guess what? Those goldfish learned to only pressed the lever in the right time frame. At that feeding time, they even hovered around the lever in anticipation!

But if you STILL are in doubt… Just listen to this last example: Researchers in Israel trained some young fish for one month to come to food at the sound of a bell. After that… … They released the fish into the sea. Now get this: 5 months later they played the sound over speakers. And the fish all came swimming back!

Chances are, the Memory of a Goldfish is FAR longer than 5 months…

All of the times in those tests were set as the goal. Finding out when the fish actually forgot something wasn’t part of the test. This means goldfish can possibly remember things for even longer. For example: As you may know, the carp is the granddaddy of the goldfish.


goldfishes in a pond
Image Credit: Monsterkoi, Pixabay

Goldfish are really modified carp, which look different on the outside but haven’t changed much on the inside (aside from perhaps more compressed organs in fancy goldfish, which makes them more sensitive when it comes to diet.) Interestingly enough, carps that were caught on the hooks of a fishing rod avoided lures for at least a year!

So, exactly how long is a goldfish memory? We don’t know 100% for sure… It hasn’t been tested for long enough to find when goldfish actually forget something. But judging by the evidence we’ve looked at, it’s safe to say they have as good a memory as most other small pets, which is at least several months if not YEARS. Hopefully this article brings to light the nail in the coffin for this 3 second goldfish memory fallacy.

Key Takeaways

Things really change when you realize a goldfish memory may span MONTHS – not seconds. Most who keep goldfish discover their pet is very quick to catch on where the food comes on, sometimes even being trained to beg at one side of the aquarium!

Dr. Culum Brown has studied fish behavior for over a decade and maintains that fish are intelligent creatures who learn the lifelong skills of avoiding predators and foraging for food. He has this to say about whether or not it is important to make their habitat more interesting.

“Definitely – I think the more complicated you make your fish tank, the happier your fish is gonna be.”  In fact, the best thing to do is to keep changing it around, so make it interesting for them. You’ll find that if you do that, your goldfish will be much more active and much happier in general.”
Image Credit: antoni halim, Shutterstock

But Don’t Goldfish Have Tiny Brains?

Fun fact: A fish’s brain is 380,000 times smaller than the brain of a human baby. So there’s no denying it is tiny. It is true that they have small brains, but only in comparison to larger living things. Their brain is sized in proportion to the rest of them, which is just as small in comparison to a person. The bottom line? Small does not mean stupid! There are plenty of other animals, such as mice, birds and reptiles which have the ability to retain information for extended lengths of time.

fish divider


Contrary to popular belief, goldfish do not have a 3 second memory. Researchers have conclusively found that their memory can last for several months, with some estimates putting their cognitive recollection abilities at several years. We hope this article has helped you better understand the cognitive faculties of goldfish.

Featured Image credit: Huy Thoai, Shutterstock

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