Fish are peculiar creatures with exceptional abilities, despite their limitations compared to humans. Because of their environment and need to survive, questions arise on their senses, particularly the eyes.
For instance, can they see color? If they do, what colors do they see? How well do they see? It turns out fish have a different view of the world than us humans, maybe even better.
Also, is it possible for fish to see more colors than humans, even in the deep, dark depths of the sea? What about their eyes make them different from us humans?
Let’s dive in and explore more about fish and their capabilities to see color, and take a closer look at their eyesight.
Are Fish Eyes Different Than Ours?
Discovering that fish’s eyes have similarities and disparities to the human eyes shows they aren’t that much different from us.
For example, fish’s eyes tend to be on the sides, while human eyes are in front, giving a binocular look. This changes the depth of perception, where fish are at a disadvantage. It’s why when they’re feeding on algae near rocks or anywhere else, they’re close and don’t stray too far. Those who go fishing for sport know this secret.
Likewise, humans have pupils that dilate, but do fish? Most fish have a fixed pupil, while some fish, such as sharks, have growing pupils.
What Colors Do Fish See?
To see color, there are color detectors behind an eye’s retina, such as cones that must be present. Humans have three different cones called red, green, and blue. Some fish, on the other hand, have red, green, blue, and ultraviolet.
Because fish have an extra cone in their eyes, they can see more colors than humans. This includes all the colors of the rainbow and even more across the spectrum.
Depending on where they are in the ocean, they can see a vast amount of colors. The fish that are more on the surface where the most sunlight occurs have this capability.
Let’s not forget deep-sea fish, where color is scarce. Surprisingly, fish in the depths of the ocean can see color, but differently than we might imagine.
What About Fish in the Dark Depths of the Ocean?
Unfortunately, fish in the ocean’s deep dark depths cannot see the same amount of colors as fish that hang around the surface.
However, they see enough to survive and avoid predators. It’s possible due to the formation of their eyes and genes.
When you think of fish, you don’t think of their genes, but due to evolutionary circumstances, it turns out fish in the dark depths of the sea have different genes than those who live on the surface. How is this possible?
Scientists discovered that deep-sea fish lost the genes that allow them to see red and ultraviolet parts of the spectrum because those wavelengths do not penetrate the deep sea. Looking at the genetic make-up of 101 deep-sea fish, it turns out some of the fish had extra copies of genes that can see dim lighting. These genes allow the fish to see more blues and greens that we can imagine.
Seeing beautiful hues of blue and green wavelengths allow many of these deep-sea fish to avoid bioluminescent predators. Bioluminescence, oddly enough, is an attractive, bright blue-green color that is seen in the ocean at night, given off by different marine life and invertebrates.
Wait, Fish Are Not Color Blind?
As mentioned earlier, fish that come into contact with sunlight will see various wavelengths of color, especially if they possess the cones to see these colors. Usually, fish that inhabit the surface do have these cones in their eyes. Deep-sea fish don’t have the same capabilities due to lack of sunlight, but they see different colors that aid their survival.
Simply put, it depends on the visibility of the fish, its location, and its species. Most fish are not color blind, although it depends on how much light is available. What does this mean? At night time, the color cones in their eyes retract, because of the absence of light, meaning surface fish are color blind at night only.
The bottom line is that fish living on the water’s surface with large amounts of sunlight can see color. When it is night time, even with light from the moon, they are color blind, but only when light visibility is the lowest.
Fish Have Good Eyesight for Their Environment
Sure, fish have their differences from humans, but that doesn’t mean they can’t see well. Fish have good enough eyesight for their survivability.
Unfortunately, fish tend to be near-sighted creatures with inferior distance vision. The placement of their eyes on the sides of their heads also may allow a semi-blind spot, making them susceptible to danger or being hooked by a fisherman. However, fish have a better peripheral vision because of round lenses that protrude forward, making a difference when swimming away from predators.
Now, fish do have smaller brains than many other living organisms. They may not be able to process what they see visually like humans, for instance. Does this mean they have poor eyesight? Of course not.
For what they’re capable of, they can see through murky waters, enough to distinguish what they perceive. Although, depending on the fish, they can confuse a predator hiding as a part of a colony and meet an unfortunate demise, as you may have seen while watching nature documentaries.
Despite these shortcomings, fish can see underwater better than humans, including a wider variety of colors if they’re living on the surface of the ocean.
In conclusion, it turns out fish can see color and superior to humans, thanks to an extra cone in their eyes that allows them to see ultraviolet wavelengths.
Fish deep in the ocean have adapted to seeing different color hues we can’t fathom, but enough to avoid predators and survive the dark, cold depths of the sea.
Lastly, we can also say that fish do have good eyesight, as it’s good enough for their habitats and has allowed them to survive millions of years.