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23 Interesting Goldfish Facts

Over 4.8 million goldfish are sold as pets each year. Sounds pretty surprising, doesn’t it? But, besides their common gold appearance, goldfish have a lot of unique traits and features that most of us don’t know about.

So, while you are here, let us explore some of the goldfish facts for kids that you probably didn’t know about.

Basic Goldfish Facts

  • Name: Goldfish
  • Scientific Classification: Carassius auratus
  • Latin Name: Karass
  • Appearance (physical characteristics): Two sets of paired fins, three single fins, large eyes, orange-gold in color, black spots with olive-green spots, lack barbels.
  • Different Types of Goldfish: Orandu, ranchu, common goldfish, fantail, black moor, comet, goldfish, ryukin, bubble eye, Lionhead, etc.
  • Size and Weight: up to 23 inches; weigh up to 9.9 pounds
  • Habitat and Range: Freshwater
  • Diet: OmnivoresLife Expectancy: up to 10 years in captivity; up to 40 years in wild

23 Interesting Goldfish Facts

When you talk about aquarium pets, goldfish are undoubtedly one of the most popular aquatic pets that people talk about. But, despite their popularity, there are so many hidden facts that many people don’t know about.

Let us look into some of the most underrated facts:

  1. Surprisingly enough, goldfish have brains. If you thought they were aimlessly moving around, goldfish are smarter than you think. They spend most of their time finding the best spot to relax, interact and engage with the other tank mates.
  2. Goldfish eyes can detect ultraviolet and infrared rays. In addition, instead of seeing a combination of three different colors like humans, goldfish eyes can see a blend of four different colors. The primary reason behind this additional feature is to help them hunt for food in their surroundings. However, their eyes are on either side of their face, creating a blind spot in the middle of their face.
  3. When it comes to their vision, they cannot see very far ahead in the water. Also, they don’t have eyelids, which prevents them from closing their eyes. So, even when they are sleeping, their eyes remain open. So, if you have a pet goldfish, we’d recommend switching off the light in the water body to ensure they get good sleep.
  4. Due to consistent cross-breeding, goldfish have mutated and evolved in terms of their genetic structure, color, and appearance. As a result, over 200 different types of goldfish species are available.
  5. Like humans, goldfish taste their food before they gobble things down. So, when you offer them food inside the aquarium, you will often find them nibbling on the food before they wipe it out. And a unique fact about goldfish is that they taste with their lips and not their tongue. The majority of their taste buds are on their lips. Goldfish don’t have a tongue.
  6. Although goldfish look very delicate, they are adamant and hardy. Even with a change in the water parameters, they can easily sustain the rough conditions. They can quickly acclimatize themselves to the change in water pH, temperature, and living conditions.
  7. They have their teeth in the back of their throat. Also known as pharyngeal teeth, goldfish are the only species on Earth with their teeth at the back of their throat. Like the standard functionality of the teeth, they help in grinding down the food for easier digestion.
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  8. Surprisingly, there is no “average” size to a goldfish because they can dramatically vary in size. Most of the time, a goldfish grows depending on the tank size. If kept in a smaller tank, they will have lesser growth, but when kept in larger aquariums. In the wild, a goldfish can grow up to the size of an adult carp.
  9. Goldfish don’t have a stomach. Instead, they typically digest their food through different parts of the intestine. So, the duration of the digestion is relatively more minor, leaving them hungry quite frequently than most of the other fish species.
  10. As adorable and innocent as they look, goldfish are invaders. This means they will quickly take over the native species when you leave them in the wild. So even in captivity, it is essential to choose suitable tank mates for them. They are very prolific cross-breeders too, which results in drastic genetic mutations where they live.
  11. Did you know that you can tell a goldfish’s age by its scales? Every year a goldfish is alive, it develops individual rings on the scale, signifying its age. Also known as circuli, these rings are very similar to the rings that you find in the trees as they age. Only experienced professionals can read and analyze the circuli.
  12. Despite their lack of tongue and affected sense of taste, goldfish have very sharp additional senses, especially when it comes to their smell and sight. Their sense of hearing is very elevated than other species.
  13. Goldfish aren’t naturally gold in color. They get their color from the sun and other light sources. If you leave a goldfish without any light source, they will soon turn white and lose all the pigment from their bodies. Some goldfish turn albino due to lack of light, while others are born like that and never gain pigment on their bodies.
  14. Goldfish have a longer lifespan than other pet fish species and can live up to 10 years and more in captivity. However, they can live up to 40 years in the wild.
  15. One of the unique traits of a goldfish is that it can detect changes in water pressure. They can assess and analyze the change using the water currents and the vibrations in the water. They have to thank their lateral line for this unique trait that helps them navigate through the water and prepare themselves for any drastic changes.
  16. You will often find a goldfish making noise through its nose. They mimic sounds of squeals and grunts that most researchers believe are for communication. You will often hear this sound when they are eating their food or fighting with other fish in the tank.
  17. Goldfish don’t like taps on their aquarium. If you are trying to get their attention by constantly tapping on the tank, it can stress them out. In addition, their otolith or internal ears are very sensitive to the knocking sound, so they often perceive it as a threat and stress themselves out.
  18. If goldfish lose their skin or fins in a fight or due to injuries, they can quickly regenerate them. Regeneration of the skin and scales is a common goldfish trait. However, ensure that you have a clean tank to support the process.
  19. A female goldfish can lay up to 1000 eggs during its breeding cycle. However, not every laid egg is fertilized and results in a goldfish fry. However, their reproduction rate is comparatively quite fast, which is why they are so easily accessible across the world.
  20. When bred with koi, Goldfish can produce cross-bred offspring, but the fry is infertile and cannot be bred any further. One of the most common examples of a crossbreeding goldfish with koi is the black comet goldfish.
  21. Contrary to popular belief, goldfish have a five-month memory and not three-second memory. Even studies prove that as a fact.
  22. As morbid as it sounds, goldfish can eat themselves to death. But, since they don’t have a stomach, it is tough to know when they are full and satisfied. So, they can often overeat to an extent that they can die. But, on the flip side, they can live without food for up to 3 weeks.
  23. If you want to bond with your goldfish, hand-feed them. It is 100% safe and allows you to form a bond with the fish. However, it might take some time for the fish to get used to the hand feeding.


How many of these goldfish facts did you know about? Although we have shared the top 25 facts, those are just the beginning. There are so many other goldfish facts left to cover in the future.

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