Goldfish Facts: 20 Mind-blowing Facts About Goldfish

We love fascinating goldfish facts here at The Goldfish Tank – and there really are some weird and wonderful facts about goldfish!

Top Goldfish Facts

Check out the amazing goldfish facts below to better understand your fish.

The more goldfish facts you learn and the more you know about goldfish, the better you will be able to care for them!

Goldfish don’t have stomachs

Goldfish don't have stomachs

Goldfish don’t have stomachs and should therefore be fed easily digestible food in lots of small feeding sessions, rather than lots of food at once. This is also why goldfish produce so much waste and why you need a filter to keep their water clean.

Goldfish have been known to live for over 40 years

With the proper care, goldfish can live for decades. This goldfish was said to be 45 years old. 

The collective noun for goldfish is “a troubling”

Just like you’d say “a herd of cows”, you’d say “a troubling of goldfish”!

Goldfish can recognize people’s faces

Goldfish can tell different faces apart and are able to distinguish between different shapes, colors, and sounds.

Goldfish have a memory span of at least three months

Many people say that goldfish have a memory of just a few seconds, but this is a myth! Goldfish have a memory span of at least three months!

Goldfish can grow to over a foot long

Goldfish can be stunted by being kept in tanks that are too small for them and where the water quality is poor. This means that they don’t reach their full potential size. However, goldfish can grow to be over a foot long when kept in the right environment.

Selective breeding has led to a huge variety of goldfish shapes and colors

Humans have bred many different varieties of goldfish.

Goldfish can’t close their eyes

Goldfish have no eyelids, so they have to sleep with their eyes open!

Goldfish have been kept as pets for over 2000 years

Keeping pet goldfish dates all the way back to ancient China!

11 Famous Types Of Goldfish Known

Goldfish come in various types, each with its unique characteristics, features, and appearances. Here are some popular types of goldfish:

Common Goldfish: The common goldfish is the typical goldfish that most people are familiar with. It has a sleek, elongated body and comes in various colors.

Shubunkin: Shubunkin goldfish are known for their calico coloration, which includes a mix of red, orange, yellow, blue, black, and white patches. They have a similar body shape to the common goldfish.

Goldfish come in various types, each with its unique characteristics, features, and appearances. Here are some popular types of goldfish:

  1. Common or Comet Goldfish: The common goldfish is the typical goldfish that most people are familiar with. It has a sleek, elongated body and comes in various colors.
  2. Shubunkin: Shubunkin goldfish are known for their calico coloration, which includes a mix of red, orange, yellow, blue, black, and white patches. They have a similar body shape to the common goldfish.
  3. Comet Goldfish: Similar to the common goldfish, comet goldfish have a long, slender body and a flowing tail. They are often characterized by their single tails, which can be quite lengthy.
  4. Fantail Goldfish: Fantail goldfish have a double tail and a rounded body. Their fins are well-developed and flow gracefully. They come in various colors, including orange, red, white, and calico.
  5. Black Moor: Black moors are known for their distinctive appearance, with a deep black coloration and telescope eyes that protrude from the sides of their heads.
  6. Ryukin: Ryukin goldfish have a hump on their backs behind the head, and their bodies are deep and short. They can come in various colors, and their tails are usually double and flowing.
  7. Oranda: Oranda goldfish are characterized by a fleshy growth or “wen” on their heads, which becomes more prominent as they mature. They can have various tail types and colors.
  8. Linhead: Lionhead goldfish are known for their hood or head growth, resembling a lion’s mane. They have a round body and short, stubby fins.
  9. Ranchu: Similar to the lionhead, the ranchu goldfish also has a distinctive head growth, but it lacks a dorsal fin. It has a rounded body and is often referred to as the “king of goldfish” in Japan.
  10. Pearlscale: Pearlscale goldfish have a rounded body and distinctive scales that resemble pearls. They are often metallic or matte in color.
  11. Telescope Goldfish: Telescope goldfish have protruding eyes that resemble telescopes, giving them a distinctive appearance. They can have various body shapes and fin types.

These are just a few examples, and there are many more goldfish varieties, each with its own unique charm and features. It’s important to note that goldfish care requirements may vary depending on the specific type, so it’s essential to understand the needs of the particular goldfish variety you choose.

Goldfish can see more colors than humans can

Goldfish don’t like to be kept in the dark and, unlike humans, they are able to see ultraviolet and infrared light.

Goldfish don’t urinate

No fish urinate. Instead of expelling ammonia by urinating (as mammals do), fish filter ammonia from the water using their gills.

Goldfish can live in very cold water

The metabolism of a goldfish will slow down significantly in cold water, almost like they are hibernating. This means that goldfish can survive in very low temperatures, sometimes even in ponds that have frozen over for the winter!

Goldfish and Koi are NOT the same species

Goldfish and Koi are both members of the carp family, but they are not the same species. They can interbreed but their offspring will be sterile.

Goldfish lay a lot of eggs

A female goldfish will lay hundreds or even thousands of eggs in a single spawning. However, only a small proportion of these will be fertilized.

It’s possible to breed goldfish and care for baby goldfish in a home aquarium.

Goldfish change color depending on light levels

If your goldfish is kept in the dark at night, you may notice that its color appears faded when you switch the aquarium light on again in the morning. Also, goldfish kept outdoors with greater exposure to natural light are usually more colorful than goldfish that are kept indoors.

Goldfish are omnivores

Goldfish will eat plants, insects, small crustaceans, and sometimes even other small fish! We have several articles on goldfish food!

Goldfish have been available in Europe and the US for a long time

The domestic goldfish originated in China but was introduced to Japan in 1603, to Europe in 1611, and to North America around 1850.

Goldfish were once traditional anniversary gifts

Goldfish were once traditional anniversary gifts

In the early 17th century it was traditional for men to give their wives a goldfish on their one-year anniversary! This was meant to symbolize a prosperous future, but the tradition died out when goldfish became more readily available.

Touching a goldfish can endanger its health

You should never pet your fish, as you may damage the slime coat that protects its skin from infection.

Goldfish get used to being around humans

Goldfish can get used to humans and will eventually stop considering them a threat. This can make it possible to feed your goldfish by hand!


  1. What are 5 facts about the goldfish?
    • a. Goldfish have a remarkable ability to remember things for months, debunking the myth that they have a three-second memory span.
    • b. There are over 125 varieties of goldfish, each with distinct characteristics and appearances.
    • c. The oldest recorded goldfish lived for 43 years, showcasing their potential for a long lifespan.
    • d. Goldfish are social creatures and thrive in the company of other goldfish.
    • e. Contrary to popular belief, goldfish are not native to North America but originated in East Asia.
  2. What makes goldfish happy?
    • Goldfish are happiest when they have a spacious and well-maintained environment. Adequate tank size, clean water, proper filtration, and the company of other compatible goldfish contribute to their well-being. Providing a varied and nutritious diet, along with opportunities for mental stimulation, also enhances their happiness.
  3. What is a fact file about goldfish?
    • A fact file about goldfish would typically include essential information such as:
      • Origin and history of goldfish
      • Various goldfish varieties and their characteristics
      • Anatomy and physical features
      • Ideal habitat conditions, including tank or pond setup
      • Nutritional needs and feeding habits
      • Common health issues and preventive measures
      • Lifespan and breeding information
      • Fun facts and trivia about goldfish
      • Cultural significance and symbolism in different societies
  4. How long do goldfish live?
    • The lifespan of a goldfish varies depending on factors like care, environment, and genetics. On average, with proper care, goldfish can live between 10 to 15 years. Some varieties, under optimal conditions, have been known to live even longer, surpassing 20 years.
  5. What do goldfish do for fun?
    • Goldfish engage in various activities for entertainment and stimulation, such as:
      • Exploring their environment and swimming through tank decorations.
      • Interacting with other goldfish, displaying social behaviors.
      • Playing with floating objects or toys placed in the tank.
      • Responding positively to human interaction, especially during feeding time.
      • Exhibiting playful behaviors, like chasing each other or darting around the tank.

We hope you enjoyed these goldfish facts and that they help you understand your fish better. Keep exploring The Goldfish Tank to learn more!

And if we missed any of your favorite goldfish facts, please share them in the comments.

23 thoughts on “Goldfish Facts: 20 Mind-blowing Facts About Goldfish”

  1. I have an integrated light and filter on a Nano chi tank with two cold water Goldfish. Can I turn this off at night and how long would be ok if I did this when I went on holiday.

    • Hi Peter, thanks for your comment,
      As long as the filter stays on, you can turn the lights off at night time, it is best to do this on a 12 hour on 12 hour off basis to allow your goldfish to sleep.
      You should be able to leave your lights off while you are on holiday, as long as there are no live plants in there which could die from lack of light for too long.
      I will also mention that your goldfish will outgrow the Fulval chi tank, so you may want to consider upgrading once they get a little larger.
      hope this helps.

  2. Hope someone can answer this question…our 3-year old Koi fish Crowley and our (once-a-carnival prize) 8-year-old comet goldfish George (she’s now as big as Crowley) are now the king and queen of our pond. They have had 3 crops of fry (little oddly-colorless fish who I have had to re-home to pond-owning friends) over the last 2 years…and we keep having to make the pond bigger to keep the water quality intact.
    My question: how long will poor George be fertile?

    • Hi Julie, thanks for your comment,
      It is interesting to hear that your koi and goldfish have spawned together.
      As for your question on how long they will remain fertile, as goldfish lay eggs, they are not like mammals who reach a menopause state at a certain age, so George may continue to spawn for the majority of their life, which can exceed 20 years if looked after properly.
      As for your water quality, try feeding less, add more live plants or clean out your filter.
      Hope this helps.

  3. Omg ty so much i am working on my writing and I need facts for goldfish for my topic sentence and my report you helped so much ty (thank you ) 🙂

  4. I had two goldfish in the same tank. One died and the other one carried him around the tank on his back. Is it possible he had empathy for him? What other reason could there be?

    • Hi Diane, thanks for your comment,
      Perhaps you are right, or maybe your other goldfish has inspected the body, mouthed at it and the body was stuck on its lip or there could be another reason.
      Either way, always be sure to remove dead bodies from your fish tank as they cause high spikes in ammonia levels as they decompose.

    • Diane, I have had goldfish ever since my niece won a goldfish at a church festival and my SIL refused to let her keep it. I keep mine in a tank with a filter and different decorations. I had a murder victim skull in my tank for Halloween, but not a real victim. The skull was an aquarium ornament. I felt bad when my goldfish Zeke died. I still have little Edward. I never saw any of my goldfish carrying their dead friends around. I just see the bodies on the bottom of the tank. Maybe they do feel bad about the death. My goldfish and guppies swim up to the top when I bring them food.

  5. Great facts, thank you.

    My question is, my 11 goldfish are all over 10 years old and don’t swim around much anymore. One actually sleeps on the floor most of the time. When it’s feed time she gets up and swims around and has a feed. Could they just be geriatric? They seem healthy.

    • Thanks for the supportive feedback! love to hear you found our page interesting.

      To answer your question; possibly, it can be fairly common for goldfish to sleep on the floor, if like you said they are otherwise healthy, then I’m sure its not much to worry about.
      just look out for key signs of stress, like rapid gill movement, loss in colour, appetite reduction, etc.
      Keep on top of that water quality too, and you cant really go wrong 🙂

  6. Thank you. This helped me to write most of my book report. Also I’m in fifth grade so I learned a lot of new facts about goldfish.

  7. My goldfish are now too big for their 20 gallon tank, so I purchased a larger one for them. How do I transfer them to the new tank with the least amount of stress (for all of us!). Do you have an article on this?

  8. Like to see info on water coolers. I live in southern US and it is a challenge to cool the water off in the summer even with a/c running. I solve this by keeping a screen on top instead of lid and pointing a fan at it. Tank 125 gal 3 fish almost 10 yr old so this setup obviously works.

    • Hi Jesse,

      Thank you for the suggestion, we definitely need to talk about them more, since they are great for people who have overheating troubles, although they can sometimes be a little expensive to setup.

      On a budget build, using fans and frozen water bottles do the trick for us.

      But definitely something worth going into more detail about, thanks for your comment 🙂


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