A lot of fish do have a version of night vision to be able to see in the dark. While this serves them quite well, for the most part, fish use their other senses to be able to work out where things are usually using their touch and smell.
A lot of fish also have a lateral line system to work out where objects and obstacles are located. For example snook have a pronounced lateral line that helps them to catch their food in their dark and dingy water.
Many types of animals have a varying level of ability to see in the dark and fish are not exempt from this.
An Explanation Of If Fish Can See In The Dark
If you own fish as pets you can quite commonly see them swimming once it has gotten dark, especially if you keep nocturnal species.
Even if you do not own fish there is a strong likelihood that you have seen fish move and be able to swim relatively accurately even when it should be quite hard for them to be able to see.
While being able to sense obstacles and how to avoid them for humans is a skill usually attributed to sight and is what a lot of people would consider seeing, this is not the same for fish who experience their surroundings differently.
The way we see can be explained as how fishes ‘sense’.
This is how fish are able to notice their surroundings so well while swimming in the dark because darkness impedes seeing, not sensing, this is why a lot of fishes do not require night vision as seeing is not as important of a sense for fish.
Most fish have rows of organs that are pressure-sensitive and these are more commonly referred to as lateral lines, these tend to be located on the sides of fish’s bodies and will let them sense anything around them.
This sensing includes other animals, any objects or obstacles, or even adapting to changes in the movement of the water or its changing pressure.
Compared to most other underwater fishes, eels and sharks sense underwater activity differently.
These creatures have a specific organ that will allow them to sense and detect an electric field that would be produced from when other animals move.
Can Fish See In The Dark In A Fish Tank?
Since aquarium owners are some of the most likely people to see fish moving and swimming in the dark, they are some of the most likely to ask if fish can see in the dark.
For the most part, fish that are kept in fish tanks do not see in the dark but instead use the aforementioned sensing.
These fish simply move forward by sensing their environment without needing to see in the dark.
This is due to how most of the species that are living in fish tanks have not needed to adapt to see in the dark therefore it is not a necessary skill and sensing will be enough for them.
Most fish that are based in aquariums will spend most of their time that is spent in the darkness resting not needing to move much and will not need to have the precise movement that necessitates sight.
Can Fish See In The Dark In An Ocean?
Most fish that live in oceans are used to living their lives mostly surrounded by very dark water and sometimes complete darkness.
Most ocean fish can actually see and sense their surroundings much better in the dark than they can in lighter conditions as it is what they have been conditioned to.
They see better in the dark much better than fish in other conditions and much better than humans can.
These fishes tend to have eyes with a spherical lens which gives them significantly stronger peripheral views.
These fish have retinas that will capture significantly more small frequencies of light and this will give them much clearer vision in dark environments.
These fish have the same lateral line system however this is significantly adjusted to help them sense objects in deeper pressures that come with the ocean.
Can Fishes See At Night?
Most fish have some kind of night vision and some fish will possess a particularly sharp sense of sight at night depending on their conditions.
These fish that have stronger nighter vision will have specific chemicals present in their eyes which give them vision of colors within a wider range of spectrums as well as unique UV frequencies.
These fish will also have a specific coating over the surface of their eyes which gives them seamless vision during the night.
These layers that are on top of the fish’s eyes are what lets them see both dark and light as well as gray shades.
If fish do not possess eyes built specially built for night vision like these fish they most likely are able to adapt with their sensory organs to be able to move well at night.
Which Fish Are Able To See In The Dark?
There is a wide variety of fish that have been discovered that are able to see in the dark and that have adapted over time to be able to achieve this.
A few of these specific species that are capable of seeing in the dark are; silver spinyfins, tube eyes, glacier lanternfish, and longwing spinyfins.
What makes these fish unique is that they all reside between 1000-2000 meters under sea level.
Takeaway
So while there are many fish that have adapted to be able to see underwater, the majority of fish do not need to see underwater as they have lateral line systems that allow them to sense changes in the water instead of needing to see them!
