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16 Interesting Goldfish Facts

Goldfish are one of the world's most famous pets. These vibrant and mesmerizing aquatic creatures have captured the hearts of many with their stunning colors and graceful movements. Originating from East Asia, goldfish belong to the carp family and are known for their distinctive appearance and unique behaviors.

Interestingly, goldfish are descendants of a less colorful kind, the Prussian Carp. Their recognizable golden sparkle results from careful human breeding over centuries. This introduction to goldfish facts will ignite your curiosity about these aquatic creatures' unique biology and history.

And for more fishy fun, discover a treasure trove of fun facts about fish! Or look at our fish quotes and sayings celebrating the wonders of marine life.

16 Facts about Goldfish

goldfish front view
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1. Goldfish’s popularity started in China.

Goldfish (Carassius auratus) became famous during China's Tang Dynasty. Interestingly, they didn't shimmer in gold as we know them today. Instead, they wore simple silver or grey scales, a testament to their humble beginnings. During this time, only royalty could own pet goldfish. Ordinary folks were banned from owning a yellow goldfish.

People kept them in large water gardens, not tiny bowls. However, their colors gradually transformed through careful breeding into the dazzling gold we see today.

2. There are 200 varieties of goldfish.

goldfish close up view
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Goldfish are incredibly diverse; through selective breeding, there are now over 200 varieties of goldfish with different colors and types.

They go beyond the traditional orange fish (or Poster Fish). There are also fancy breeds like the Oranda, with an unusual, brain-like growth on its head (known as a 'wen'). The Ryukin, a native of Japan's Ryukyu Islands, stands out with its deep body and high dorsal fin. These fishes make a bold statement in any tank.

Furthermore, the Fantastic Fantail is also a popular choice for many home aquariums. Its split tail fins spread out like a fan, and it comes in a range of striking colors, not just gold but red, white, or even a kind of patchwork calico mix.

3. Not all goldfish are gold, and they can change color. 

Goldfish are known for their golden color, but they can also surprise you with a stunning range of shades. Their color palette is impressive, from fiery reds and oranges to crisp whites, jet blacks, and even blues.

Moreover, goldfish can change color. Their diet, sunlight exposure, and age can influence their final color2. For example, the Black Moor Goldfish, known for its dark hue, might decide to become gold just because it wants to. The Blue Oranda can transform from dull gray to vibrant blue.

However, environmental factors also affect their coloration. Lack of sunlight means they can't produce colorful pigments on their skin, resulting in white goldfish. These white goldfish have no pigments and are susceptible to UV rays.

4. They can outgrow your regular fish bowls.

One of the fantastic facts about goldfish is their ability to keep growing. Goldfish are often seen as small pets in glass bowls but can grow much larger. In the wild, the largest goldfish can reach an impressive size of up to 14 inches.

Throughout their lives, goldfish undergo 'indeterminate growth.' The term means genetics don't influence their size; their living space determines their size. In short, the size of your goldfish's tank will affect the size of your goldfish.

When provided with a suitable environment, like rivers or large outdoor ponds, goldfish can reach their full-size potential. So, consider the potential size of your fish tanks, as they can grow much larger than we typically imagine.

5. They have good vision.

group of goldfish
Photo by pouria oskuie on Unsplash.

What's next in our list of goldfish facts? We will discuss their fantastic vision. Though goldfish have a limited amount of senses, they have unique eyes. Thanks to their four types of cone cells, they can see a broader range of light, including ultraviolet and infrared.

This helps them find food, spot danger, and choose mates. Their eyes give them a wide view of almost 360 degrees, with only a tiny blind spot. They lack taste buds on their tongues or in their mouths. Instead, they rely on their sense of smell to locate and identify food. They switch to a black-and-white view at night for better navigation in the dark.

6. They have a fantastic memory.

Goldfish are much more intelligent than their reputation suggests. Contrary to popular belief, studies have shown that goldfish can remember things for up to five months. For example, they can learn to associate actions with results, such as nudging a lever to get food. Even after months, they remember this feeding drill.

They can also remember specific sounds associated with feeding time and recognize their tank's layout, other fish, and tank mates. These memory skills are essential for their survival in finding food and avoiding predators.

7. Wild goldfish are river dwellers.

goldfish veiltail
Photo by Hans on Pixabay.

Giant goldfish are freshwater fish that have lived in China's rivers, lakes, and ponds for over a thousand years. They prefer temperate environments and thrive in water temperatures between 20°C and 22°C.

Goldfish live below the water's surface, where it is safer from predators, and the temperature remains consistent. Their natural habitat is filled with aquatic plants, which provide proper nutrition and hiding places.

Moreover, they are skilled at finding food in muddy areas and riverbeds using their sensitive barbels. They can adapt to slightly alkaline water with a pH between 7.0 and 8.4. They can also survive in stagnant water, but environmental changes can harm their health and survival.

8. Goldfish will eat everything.

Goldfish are versatile eaters, enjoying a wide range of food in their underwater world. They eat plants, insects, smaller fish, fish eggs, and other small creatures. They sometimes even eat small fish. Similar to humans, goldfish taste their food before devouring it.

This adaptability in their food choices allows them to thrive in various environments. Moreover, their diet can impact their vibrant colors. Natural pigments in their food, called carotenoids, contribute to their stunning appearance. Therefore, goldfish eat to survive and enhance their beauty.

Are you interested in learning more about omnivore marine animals? Discover fascinating sea turtle facts!

9. A female goldfish can lay thousands of eggs.

Female goldfish can lay hundreds or even thousands of eggs at once. These eggs stick to various surfaces in the water to protect them from predators1. The male goldfish fertilizes the eggs externally, and the tiny fry develops inside their shells. After hatching, the dark-colored fry camouflages themselves and gradually turns golden as they grow.

10. They live long.

oranda goldfish
Photo by Walter_Navarro on Pixabay.

Some goldfish species naturally live longer than others. Goldfish can live up to 40 years with proper care. Factors like temperature, tank maintenance, space, and genetics influence their longevity. Maintaining a suitable environment, including water temperature and space, promotes their health and reduces stress.

11. They don't have eyelids.

Another interesting fact is that goldfish always open their eyes because they don't have eyelids. But that doesn't affect their vision at all. Moreover, goldfish protect their eyes through a transparent layer called the cornea that covers their eyes.

This cornea helps protect their eyes from potential damage caused by debris, pollutants, and other harmful substances in the water.

12. They are considered symbols of good luck.

goldfish swimming upward
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Goldfish are highly valued in Feng Shui, an ancient Chinese art that seeks harmony between people and their environment. In Mandarin, the word for fish sounds similar to terms for 'wish' and 'abundance,' symbolizing wealth and prosperity.

The number and presence of goldfish in a Feng Shui aquarium are also significant. For instance, the Chinese believe in having nine goldfish, including eight gold or red ones for luck and energy and one black one to absorb negativity, bring positive energy, and financial success.

The fish's graceful swimming represents the flow of abundance, and their round bodies resemble gold coins, reinforcing their association with wealth. Accordingly, goldfish are symbols of prosperity and luck, enhancing the atmosphere and fortune of their surroundings.

13. Having a pet goldfish can be challenging.

Goldfish have a long lifespan, stunning colors, and a calming presence, making them enjoyable companions. They can also provide educational experiences, especially for children, and are suitable for small living spaces.

However, aspiring goldfish owners should note that goldfish require more tank space than tropical fish, so keeping their tanks manageable is crucial. Additionally, a pet goldfish lacks a stomach and should be fed easily digestible food in small portions rather than large quantities at once. Goldfish produce waste so often that you must use a filter to maintain good water quality in your fish tank.

Goldfish are social creatures that can recognize their owners, enhancing the bond between pets and humans. However, they do require proper care and maintenance to thrive. 

14. They are silent communicators.

Next on our goldfish facts list: Goldfish have a fascinating way of communicating, even though we might not realize it. They produce low-frequency sounds we can't hear using their pharyngeal teeth and swim bladder. These sounds convey emotions and intentions, creating an underwater symphony.

Goldfish communicate visually through color changes, body postures, and swimming patterns. They can recognize and remember other goldfish, even differentiating between species members. They also establish social hierarchies and interact with humans, responding to our actions. 

15. Goldfish are not like Koi fishes.

goldfish side view
Photo by Tinh Nguyen on Unsplash.

Koi fish and goldfish may seem similar initially, but the two have significant differences. In terms of appearance, koi fish have a longer, sleeker body shape with flowing fins, while goldfish have a rounder body shape and shorter, more rounded fins.

Koi fish often display vibrant and diverse color patterns, whereas goldfish come in various solid colors. Goldfish are also the only species with teeth on the back of their throats. Behavior-wise, koi fish are known to be more active and lively, frequently swimming and exploring their surroundings. On the other hand, goldfish tend to be more relaxed and slow-moving.

16. Goldfish can become an invasive species. 

When well-meaning owners release goldfish into foreign waters, they become an ecological problem. They compete with native species for resources, spread diseases that local fish are vulnerable to, and rapidly colonize new habitats.

A goldfish invasion threatens local ecosystems. Authorities are working to address this issue, but it raises a complex question: how can we protect the species in its native range while controlling its population in other areas?

If you enjoyed this list of goldfish facts, click on over to our goldfish quotes for a social media share or two!

Related: To further explore the animal kingdom, check out some of the other animals that start with G.


Blanco, Ayelén & Unniappan, Suraj. (2022). Goldfish (Carassius auratus): biology, husbandry, and research applications. Laboratory Fish in Biomedical Research (pp.373-408)


Komiyama, T., Kobayashi, H., Tateno, Y., Inoko, H., Gojobori, T., & Ikeo, K. (2009). An evolutionary origin and selection process of goldfish. Gene, 430(1-2), 5-11.

By Chinny Verana, BSc.

Chinny Verana is a degree-qualified marine biologist and researcher passionate about nature and conservation. Her expertise allows her to deeply understand the intricate relationships between marine life and their habitats.

Her unwavering love for the environment fuels her mission to create valuable content for TRVST, ensuring that readers are enlightened about the importance of biodiversity, sustainability, and conservation efforts.

Fact Checked By:
Mike Gomez, BA.

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