Can Goldfish See Outside of Their Tank?


Goldfish are a common first pet and can live for years when well cared for. As you watch your fish swimming around their tank, you may wonder how the world looks to them or if they can even see the dry world outside their watery home at all. 

Goldfish can see outside of their tank quite well. They can see objects up to 15 ft (4.6 m) away if the glass tank is clean, though their depth perception is poor. In addition, their memory is more than sufficient to help them remember what they see. 

Keep reading for more on how goldfish see the world outside their tank, what they can remember, and how else they navigate the world around them. 

How Goldfish See Outside Their Tanks

A goldfish’s eyes can see through a glass wall and clear water, just like a human’s can. Their eyes are structurally similar to those of other vertebrates, including mammals. You can observe this yourself by watching how the fish react to objects and people outside their tank. 

For example, once they’re used to a schedule, a goldfish may swim up to the surface and wait for food when it sees its owner heading toward them come feeding time. 

You can also do a finger test: Quickly wiggle your finger just above the water line outside the tank. You’ll see your goldfish flocking to it in no time. Perhaps the movement is similar to that of their usual food, but it seems to be evidence (albeit anecdotal) that goldfish can see outside their tank. 

Goldfish Vision

Not only can goldfish see up to 15 ft (4.6 m), but their vision is better than a human’s in some ways. As their eyes are on the side of their heads, goldfish have an almost 360-degree field of vision, though the trade-off is a not-so-great depth perception. These aquatic creatures have strong day vision and use their eyes to find food

Some fish, including the classic pet goldfish, can see more colors than humans. They have cone cells in their eyes that pick up UV light, though the overall number and type of cones will vary depending on the species. 

Of course, some fish will also have different levels of vision adapted to the environment they’re in. 

For more information on a goldfish’s eyes, like their structure, check out this article

Can Goldfish Remember What They See?

While goldfish have good vision during the day, popular myths about their memory capabilities may lead some people to assume that the fish can’t remember what they see, or at least not for long. 

As described in this Chewy article, one group of researchers taught an archerfish, a type of freshwater fish, to recognize a single human face. Afterward, the fish would only swim towards the face it had been trained to see, even when given 39 other faces to search through. 

If you’re wondering how long a goldfish can remember what it sees, an article from The University of Melbourne explains how the fish can recall something up to six months later. The article also pointed out how goldfish can get scared of new people outside the tank, which is further evidence of their strong vision and good memories. 

What Other Senses Do Goldfish Have?

Vision isn’t the only way goldfish can sense the world around them. As odd as it sounds, goldfish have a very well-developed sense of smell. In fact, their nostrils aren’t used at all for breathing, just smelling. 

Having internal ears also means that goldfish can hear sounds outside their tank, though the noise will sound different due to the surrounding water. While their sense of touch isn’t well-developed, they do feel pain. 

In addition, goldfish have a unique sensory organ known as the Lateral Line Organ. If you look at a goldfish’s side, you might see a thin line of ‘dots’ running horizontally down its body. These ‘dots’ are the Lateral Line, and the fish can sense water movements through it, helping them navigate the world around them.

Conclusion

As long as the tank and water are clear, a goldfish can see up to 15 ft (4.6m) outside of their tank. They can learn to recognize the person who takes care of them, swimming up to the top of the water to wait for food when they see their owner approaching. 

Aside from their eyes, goldfish can hear, rely a fair bit on smell, and can sense small water movements around them via the Lateral LIne sensory organ. 

Sources

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