Can Fish See Water? (Not What You Might Think)

We may earn compensation from the products mentioned in this post. See our Affiliate Disclaimer.

Fish are fascinating creatures. They come in a diverse variety of species, with different shapes, colors, and sizes. Some fish can be kept as pets, while there are those that can be eaten. However, there are some things about fish that remain a mystery to the average person. One thing that most people wonder about is: if humans can’t see air, can fish see water?

Fish can’t see the water around them. Similar to the human brain, their brains have omitted the information they don’t need to process in order to see their surroundings. So, just like you can’t see the air around you, fish can’t see water either.

Why Can’t Fish See Water?

It all has to do with how the brain works. One of the functions of the brain is to process information to react to stimuli. This role is necessary for survival.

For the brain to focus on vital information and conserve processing capacity, it filters out any unnecessary sensory stimuli. These stimuli are those that are constantly occurring in the background that the brain has grown accustomed to. For example, your brain has filtered out the sound of your heartbeat and the smell of your natural scent. This is also the reason why we cannot see our own noses or the air around us.

Likewise, a fish’s brain also weeds out the unnecessary stimuli that they encounter. As such, they are unable to see the water that surrounds them as their brain filters it out to make way for more vital processes.

How Can Fish See?

Animals have eyes that are adapted to their surroundings. Humans have blurred underwater vision because their eyes are meant to see in the air. In the same way, fish have eyes that are built to function underwater.

A fish’s eyes work like those of humans. They have the same parts, such as the cornea, pupil, lens, iris, retina, photoreceptors, and optic nerve.

The way that their eyes process images are similar too. Light enters the cornea and passes through the pupil and the lens to be focused by the retina. When light reaches the retina, photoreceptors convert it into electric signals, which travel through the optic nerve to the brain. But over and above that, there are many differences in how fish’s eyes are built and how they handle visual stimuli.

Human eyes and how humans process visual stimuli are mostly the same everywhere across the globe. However, this is not the case for fish, which live in such diverse environments. The water around them may be perfectly transparent or nearly opaque. They could be found in the murky waters or on the brightly lit ocean floor. 

Fish can live their entire lives on shiny, monochromatic sand or in the vibrant colors of coral reefs. To be able to see in a certain habitat, their vision differs depending on their environment and a variety of other variables.

How Do Fish See the World?

Fish have very wide panoramic vision due to their side-facing eyes. Their point of view can be likened to those of ultra-wide camera angles, which are aptly called fish-eye lenses. Additionally, this wide field of view is also because of the very rounded nature of a fish’s cornea. However, even though they have exceptional panoramic vision, their spherical lenses limit their visual focus.

Fish are also able to see more colors than humans. Aside from perceiving light in the red, green, and blue spectrum, they can also see ultraviolet light. This is helpful when they are trying to find brightly colored prey in the ocean’s dark depths.

Although fish have the ability to have a wide underwater view, this doesn’t mean that this is always the case. Other environmental factors can also affect the clarity of their vision. Water turbidity, which is influenced by factors such as wind, algae, suspended particles, and the sun’s angle, has a significant impact on the amount of light that penetrates underwater.

How Far Can Fish See?

As mentioned, fish’s eyes have spherical hard lenses that allow them to see clearly from a distance of one meter. Furthermore, their vision is typically focused only in the center, which means they need to look at something directly to be in sharp focus.

Humans and many other species change the shape of their lenses to shift focus. Fish adjust their focus by bringing the lens closer or farther away from the retina, similar to how a camera does. They still can’t see very far, but they usually don’t need to. In general, a fish’s eye is best suited to see motion and contrast than precise details. It’s fair to say that many fish are nearsighted.

Can Fish See Water?

Fish are incredible animals. Naturally, most people are curious about them. One of the age-old questions about fish is whether they can see water. However, due to their brain’s natural process of filtering out unnecessary stimuli, fish cannot see the water surrounding them.

Because of their side-facing eyes, fish have a very wide panoramic vision. Their spherical lenses, however, restrict their visual focus, making many fish short-sighted. As such, a fish’s eye is generally better at seeing motion and contrast than fine detail. 

Fish, like humans, depend on their sight to get around and survive in their everyday lives. Fish may not be able to see water, but they have remarkable abilities to view their underwater world.