Have you ever wondered:
Can fish see in the dark?
After all, they say the best time to fish is before the sun comes up.
But should you just stick to trying to lure a fish in with the smell of your bait? Or is presentation still vitally important?
Understanding the Eyes and Vision of Fish
The Census of Marine Life says that there are over 15,300 species of fish on the planet. They add nearly 200 species to their list every year. Scientists estimate there are still thousands of unidentified fish species that have not been discovered yet.
With so many fish across the globe, it’s unrealistic to answer the question, “can fish see in the dark?” with a simple yes or no answer. Instead, we’ll look into the anatomy of a fish’s eye and give some examples of different fish and their vision in the dark.
Fish need to stabilize images during their frequent and rapid head movements. The mechanism that stabilizes these reflexes is referred to as the vestibule-ocular reflex. It stabilizes the retina while the moves in opposite directions.
The purpose of the vestibule-ocular reflex is to keep an image or focus area in the center of the field of vision. An example of this is when the head moves to the right, the eyes move to the left.
Are you wondering about the anatomy of your pet goldfish’s eyes? According to the Journal of Neurophysiology, goldfish have three vestibule-ocular reflexes, which link the semicircular canal, contralateral abducens, and ipsilateral MR abducens.
How Can Fish See in Deep Water?
The vision of different fish also varies based on their habitat and environment. Some fish live in the deep waters known as the bathypelagic zone, lower midnight zone, or abyssopelagic zone.
Some examples of fish living in these deep ocean waters include the bristlemouth, anglerfish, fangtooth, viperfish, daggertooth, and barracudina. According to The American Naturalist in the University of Chicago Press Journals, these fish rely on hearing over vision.
Their inner ear is their most important sensory function since it also helps them respond to changes in water pressure. In addition to their hearing, these deep-water fish also rely on their keen sense of smell, according to Science Magazine.
Mesopelagic fish live in deep waters that appear dark to the human eye, but not dark for these fish. They adapted with eyes on top of their head, always facing upwards, which gives them the ability to sense light with a binocular-like vision.
Their eye placement limits their lateral vision, but they have the ability to hunt their prey in seemingly pitch-black waters. All they need to see is the silhouette of their prey to ambush them.
Some fish use bioluminescent light to detect and feed on their prey, according to Jens Hellinger and her colleagues at Ruhr-University in Bochum, Germany. These fish are commonly referred to as flashlight fish, for their ability to emit light through blinking.
Although little is known about this species, Hellinger found that they blink five times less frequently when their prey is not around. However, these tests were done in an experimental tank, and it is unknown if they behave the same way in natural conditions.
Should You Go Fishing at Night?
Contrary to popular belief, fishing at night has little to do with the fish and their vision and more to do with the fisherman. Light from the moon and stars is usually enough for fish to see, especially ones in that live near the surface or shallow waters.
The main advantage of fishing at night is that the temperature is much cooler than fishing during the middle of the day while the sun is in full force. You’ll also be competing with fewer boats and dealing with calmer waters than during the day.
Unless you are an experienced angler and boater, navigating at night is extremely dangerous and difficult. Many people believe that you can only catch catfish at night, but you can catch them at any time of the day, according to the experts at Catfish Edge.
Some catfish move to shallow water at night to feed, but there are many catfish that also feed during the day in shallow waters. Not all catfish travel to shallow water during the night. Seasons and weather also affect the patterns and habits of catfish and other fish species as well.
Lights for Your Pet Fish Tank
If you have an aquarium of fish, you may wonder or be unsure of how to manage the lighting for your pets. A general rule of thumb is 12 hours with light and 12 hours without, but check the requirements for your individual fish to make sure.
For example, according to the experts at the Pet Nest, goldfish and other similar fish can lose their color without light. Some fish may become sluggish, ill, or even stop eating if they do not get enough sufficient lighting.
On the flip side, algae grow faster in light. So if you have a light on your tank 24 hours per day, you may encounter an algae overgrowth problem. Also, some fish need a dark environment to fall asleep. Light on the tank at all times can confuse them as well.
You also want to actively monitor the temperature of your tank with or without light. Don’t let the lighting drastically impact the water temperature. Extreme fluctuations can cause harm and even death to your pet fish.
So, can fish see in the dark or not?
The short answer is yes, some fish can see in the dark and in low light. What humans may interpret as the dark is likely enough light for fish to see, navigate and feed. So this means you can fish the nights away with no worries.
Fish have learned to adapt to their environment in order see and survive. Other fish rely on their other senses such as hearing and smell in order to survive in their unique climates.
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