Can Goldfish See Color & Can They See In The Dark?

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Fishkeeping enthusiasts will be the first people to tell you that goldfish are immensely popular in the pet world. Goldfish have been kept as pets for centuries and are still one of the most popular fish to keep. Their striking colors, intelligent dispositions, and ease of care make them a great choice for both beginner and experienced aquarists alike.

Despite our ongoing fascination with these fish, many people still have a lot of misconceptions about them. Some people believe, for example, that goldfish can’t see color or that they can only see in the dark. In this article, we’ll explore whether or not these claims are true and find out just what they can and can’t see.

How Do Goldfish See?

To understand how fish vision works, we need to first take a look at the biological makeup of a fish’s eye. For the most part, fish eyes resemble that of mammals – they have a cornea, iris, and lens. However, the eye lenses of fish are more spherical in shape, compared to the more ovoid shape of mammal lenses.

The most important component of a fish’s eye is the retina. The retina contains the rod and cone cells, which are responsible for detecting light and color. In other words, the retina contains color detectors, as well as structures that facilitate night vision.

Like virtually every other species in the animal kingdom, goldfish rely on their sense of sight for survival. Tasks such as feeding, avoiding predators, and finding mates all require good vision. So just how well do goldfish see?

Do Goldfish See Color?

Simply put, goldfish can see colors much better than humans can. Humans have three types of color receptors in their eyes – red, green, and blue. Every color we observe is derived from a combination of these three colors. Goldfish, on the other hand, can not only see the types of lights and colors humans see, but are able to see things in a different light spectrum altogether – infrared light and ultraviolet light.

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Practically speaking, this makes goldfish sensitive to polarized light – those with light wavelengths that are far longer or shorter than what humans can see. Whereas humans are only able to see light with wavelengths between 400 nm and 700 nm, goldfish can see as low as 200 nm and up to 900 nm! This makes their vision superior to that of most species.

What this means for you as an aquarist is that you can create a more natural and stimulating environment for your goldfish by using light bulbs with a higher ultraviolet output. You can also use different colors to enhance your tank’s appearance. For example, blue light will make your tank look cooler and more calming, while red light will make it appear warmer and more inviting.

Can Goldfish See In The Dark?

All types of goldfish – from the ubiquitous common goldfish to the rare watonai species – have a limited ability to “see” in the dark. They are not capable of seeing in complete darkness, but their highly developed sense of smell allows them to navigate in low light conditions. In the wild, goldfish would typically only come out at night to feed, and would rely on their sense of smell to help them navigate deeper waters. 

However, just because goldfish are capable of navigating around a dark fish tank, doesn’t mean that you can forgo aquarium lights altogether! Like us humans, goldfish need a healthy balance between daylight and periods of darkness to help maintain their circadian rhythm. Natural light is great, but even a reliable artificial light placed in your goldfish aquarium will go a long way in this regard.

Because of their limited vision in a dark aquarium, it is important to avoid adding any large or spiny objects to their habitats that could potentially cause them harm. If you must add something like this to your tank, be sure to provide plenty of hiding places for your fish to escape to.

How Far Can Goldfish See?

Any experienced goldfish keeper will tell you that goldfish have a knack for finding food no matter where it’s hidden in the tank. But just how far can they see?

Well, the truth is, goldfish can’t see very far at all. Goldfish are able to see clearly for up to 15 feet, but anything beyond that is blurry. Compared to humans who can see clearly up to distances of 500 feet or more, goldfish have relatively poor vision. This isn’t really a problem for them in the wild, where they typically only need to see clearly as far as they can swim.

In captivity, this really isn’t a problem either. A typical goldfish tank is not large enough for your pet to swim more than a few feet in any direction. However, if you have a very large aquarium or a pond, you may want to consider adding a few strategically placed plants or objects to help your fish navigate. Plus, you might want to avoid startling your fish with a sudden movement if you are approaching from a distance.

Beyond these simple accommodations, there isn’t much else you need to do to help your goldfish see well in their home. So go ahead and add that brightly colored ornament or that new high-tech light bulb – your goldfish will love it!

Do Goldfish Sleep?

Goldfish in a round aquarium.

Like us, our fishy friends want to sleep at night and be active in the day. Fish sleep for a variety of reasons such as resting, repairing tissue, mating and foraging.

Goldfish have a circadian rhythm which means that they have an innate 24-hour cycle of activity and rest. This rhythm is regulated by exposure to light and dark. Your charming little pet will usually get the majority of their sleep during the night when it is dark, which is good news for you – you get to observe them being their active, lively selves in the day!

To promote healthy sleep, it is important to provide your goldfish with a dark and quiet environment at night. You can do this by turning off aquarium lights or by using a nighttime bulb. If your fish seem to be restless or stressed, you may also want to try adding a few floating plants to the tank to help create a more calming environment.

For a more in-depth look into how and when goldfish sleep, check out this article!

Can Goldfish See Better Than Other Fish?

Goldfish are probably some of the most striking kinds of fish you will ever encounter, but how does their sense of sight compare to that of other fish species? Well, the eyesight of goldfish is pretty well-developed, but many species have an advantage over them when it comes to seeing in murky or dark water.

For example, many dark water fish have evolved to have tapetum lucidum, which is a layer of cells on the retina that helps them see well in low-light conditions. This is extremely helpful because species such as catfish are most active at night. In addition, many deep sea fish and cold-water fish have special adaptations that help them see in the dark.

Goldfish in the tank.

These adaptations include things like larger eyes, pupils that can dilate to let in more light, and reflectors behind the eyes that help bounce light back to the retina. Lantern fish, which are found in the deep ocean, even have a special light-producing organ called a photophore that helps them see in the dark.

Due to their environment, goldfish have not had to evolve these special adaptations and as a result, their vision is not as good in low-light conditions as some other fish species. However, they are still able to see a lot better than many freshwater feeder fish, and can certainly see well enough to get around in their tank or aquarium. 

The Takeaway

So there you have it – some fun facts about the vision of goldfish! These fun little creatures certainly have a unique sense of sight, and we hope that this article was able to shed some light (pun unintended) on how they see the world around them. When you love fish as much as we do, it’s always interesting to learn more about their fascinating biology and quirks!

Goldfish can see colors that humans cannot see, and rely on their sense of smell to navigate in the dark. As an aquarist, it is important to understand your goldfish’s vision and use this information to create a more natural and stimulating environment for them. This way, you’ll have a bunch of happy, healthy pets in your tank!

Did you enjoy reading our article? Please leave us a comment below and let us know – we would love to hear from you! And be sure to check back in with us soon for more informative and interesting articles about the wonderful world of fishkeeping. Thank you for reading!

Wanda is a second-generation aquarist from the sunny tropics of Malaysia. She has been helping her father with his freshwater tanks since she was a toddler, and has fallen in love with the hobby ever since. A perpetual nomad, Wanda does her best to integrate fish-keeping with her lifestyle, and has taken care of fish in three different continents. She loves how it provides a nice break from the hustle and bustle of life.

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