Can Fish See In The Dark

Can Fish See In The Dark? All You Need To Know

Fish can see in the dark, but can they see as well as we can? The answer is no. However, fish can see in a fashion where they can detect changes in light and make out some shapes, colors, and see in shades of grey. Nonetheless, their vision makes it difficult for them to find food at night since they are less sensitive to changes in light than we are. However, there are some fish that have the ability to generate their own light from bioluminescence, a form of chemiluminescence, meaning it can emit light as a result of a chemical reaction.

Bioluminescent fish can produce their own light by using the enzyme luciferase to catalyze oxidation reactions in special organs called photocytes. These cells contain substances such as oxygen and luciferin; a substrate for the luciferase reaction. photocytes can be found in species of fish, jellyfish, and comb jellies. Some bacteria can also produce light through a similar process called bacterioluminescence.

How Do Fish See When It’s Dark?

Fish can see in the dark because of an extra light-sensitive photopigment called a “rhodopsin” found on cells at the back of fish eyes. These receptors allow them to sense changes in light intensity, including if there’s any light present.

Some fish can see colors, while others can only see shades of grayscale and black and white. These true-color perceivers have more cones than rods providing better vision during day or night conditions as studied with several species such as rainbow trout, zebrafish, goldfish, and carp.

Fish’s Eye Structure And Anatomy

Fish have an interesting eye structure and don’t rely on a lens to focus light onto their retinas; instead, their retina is built right into the surface of their eyes. Unlike humans, who can only see objects up close or far away by changing how much light enters our lenses from all angles, fish can perceive distance without any changes to the size of their eyeballs.

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This means that even if a fish looks like it’s staring directly at you through the aquarium tank glass wall, it can’t see you. The light can’t enter the fish’s eye because of the width and thickness of its lens but also because it can dilate or contract to adjust how much light can come in; that doesn’t mean they’re looking at a wall when they swim by your side!

Instead, what may be happening is that as soon as their eyes pass over an object on either side (like your fingers), they detect movement, which means something must have passed them and then went away from them.

Can Fish See In The Dark In A Fish Tank?

Fish can’t see very well in the dark, which is why you should never keep your fish tank lights totally off at night. However, even in pitch darkness, some fish can still sense their environment and navigate with sensory organs that detect chemical changes around them as they swim.


Fish have a way of seeing that is different from humans. They can detect changes in light and make out some shapes, colors, shades of grey. However, fish can’t see that well in the dark and can get disoriented without light so they need to be able to sense their environment or they can be lost easily. Therefore some kind of subdued lighting is preferred for a fish tank to illuminate the space a little.

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