Can Fish See Color?

The underwater world is vast and mysterious. There are so many things we don’t understand about life beneath the waves, even though water makes up more than 70% of the Earth’s surface. With so much mystery surrounding aquatic life, it can be hard to know even the simplest things for certain. For example, do fish see in color the way we do?

This article will take a look at whether different types of fish see in color, what colors fish can or can’t see, as well as some other differences between the evolution of fish eyes and human eyes.

Can Fish See In Color?

The short answer is that yes, fish can see in color. Most fish are able to see a range of colors that is comparable to normal human vision, and some fish see more or fewer colors than us.

With that said, however, color vision in fish isn’t as simple as fish seeing colors the way we do. There are several really interesting things that set a fish’s sight apart from ours. From the number of receptors in their eyes to the adaptations needed for underwater vision, to the shape of the eye itself, there are plenty of factors that affect how fish see color (as well as seeing in general).

How Many Colors Can Fish See In?

Most fish, like humans, are trichromatic. This means that they have normal color vision that can pick up all three primary colors (in vision, these are red, blue, and green). However, that doesn’t necessarily mean that fish see colors to the same capacity or in the same way as humans. Because of their trichromatic vision, fish eyes are able to see the same spectrum of visible light as humans. At least, in theory.

Because of how water affects visibility, a fish’s sight is often limited to no more than a few dozen feet. This also impacts how light travels through the water; in addition to making it darker, the water will also stop some colors of light from reaching more than a few feet beneath the surface.

Warmer tones, like reds and oranges, are stripped away. Meanwhile, colder colors such as blues and greens are more visible in the murky depths. Because red light doesn’t reach deep down into the water, seeing objects as red is difficult or even impossible. Without any red light to bounce off it, red surfaces and objects will appear black.

This means that a deep-sea fish could be red but never be able to tell.

Some fish can see even more colors, depending on how many cones and receptors their eyes have. There are fish that can see spectrums of light that aren’t visible to humans, such as ultraviolet light. Additionally, fish eyes contain rods that let them see the black and white vision. Fish use their cones during the daylight, with the rods offering better light sensitivity and perception. 

There are even fish who see in many more colors than humans. While four cones already give many fish a wider range of colors than us, some fish and other sea creatures take this to the extreme. Goldfish and zebrafish, and bluegill are examples of tetrachromats (animals who see in at four colors), but their color receptors pale in comparison to other fish like the largemouth bass and the rainbow trout, who have some of the best vision out of all fish.

And while not a fish by definition, the mantis shrimp takes the cake with a whopping 12 channels of color combined with UV receptors and the ability to detect polarized light.

Finally, certain species of fish have lower color sensitivity or are even completely colorblind. For instance, fish that hunt mostly through smell like catfish have reduced color vision, while sharks can’t see color at all.

What Differences Are There Between a Fish’s Vision and Human Vision?

As mentioned before, just because a fish has the same (or more!) color receptors in their eyes, it doesn’t mean that they have better color vision than humans. We’ve already looked at how the environment limits the amount of red light and makes it hard for fish to see the color red, but there are also other things that affect how fish experience color.

The shape of a fish’s eye is different from a human’s, as well as their positions. Fish have large lenses on their eyes that elongate their vision and make it easier to see in the murky water. This is how fish-eye lenses on cameras get their name, as the effect is similar to how a fish sees.

Not only does the shape make seeing in general easier, but it also means fish can zero in on their food more simply. The magnification effect, combined with the position of a fish’s eyes on the side of its head, means that a fish can see small prey in even the darkest depths.

If a fish can see other forms of light that are invisible to humans (like UV or other spectrums of light), then they may experience their surroundings differently. Additionally, this can change their perception of colors as a whole. Just because a fish has the capacity to see the color blue doesn’t necessarily mean that they see it in the same way as us.

For a more extreme example, some fish are unable to see the color gray as its own color, and instead see it as the absence of color.

Final Thoughts

So there you have it! While most fish are able to see the same colors as humans can, there are several factors that affect how well fish can see these colors and the way they are perceived.

Some fish are able to see many more colors and spectrums of light than humans, while others are completely colorblind or have a little-to-no vision in general. Although the range of colors that different fish see varies wildly from species to species, one thing is for certain.

With how mysterious aquatic life is, there are sure to be so many fascinating things left to discover about the creatures we share our planet with!