The sleep of fish, which are constantly in motion in water, has always been wondered. Especially those who keep aquarium fish at home, when they observe these creatures, they see that the fish do not close their eyes and continue swimming. This situation brings to people's minds the question of how a creature that is in motion all day can sleep.
Do Fish Sleep?
Living beings need sleep to keep their bodies young, to gather energy for daily life and to rest. They rest their bodies in a sort of power-saving mode. Sleeping and resting states vary in all living things. We can say that most creatures that close their eyes and do not react to external stimuli are sleeping. For example, people sleep by closing their eyes and experiencing a slight lapse of consciousness. Giraffes and horses sleep standing up due to their body structure. The parrot fish prepares a kind of sleeping bag with the mucus layer it produces around itself. It is possible to multiply examples of this.
As can be seen, every living thing has a different sleep style. As a result of scientific research, it has been understood that when mammals sleep, the part of their brain called neocortex turns off. Fish do not have eyelids or neocortex. This is where things get interesting.
How Do Fish Sleep?
Scientific research shows that fish's sleep state, unlike the known sleep state, is experienced as lower brain activity, slowing down of breathing rate and decreasing metabolic rate. So fish also sleep, but this happens in a different way than we see in other animals.
Where Do Fish Sleep?
Fish retreat under rocks or into holes where they can hide, both to rest and to protect themselves from dangers and other fish. They remain motionless in a certain area and enter a sleep state. In this way, they also take control of their energy.
The sleep of fish also varies according to species. Some lie at the bottom and bury themselves in the sand, some hide in caves, some glide in the water close to the sea surface, and some make slight fin movements to stay balanced by hanging on wood, plants, rocks and corals drifting in the water.
Most fish like to sleep in darkness and dim light. Fish, like us, have difficulty sleeping in too much light. When light disturbs fish, their sleep time becomes shorter or they cannot sleep.
How Long Do Fish Sleep?
How long and how a fish sleeps depends on the fish species, environmental factors and movement characteristics. Depending on the amount of movement of the fish during the day, the sleep duration may increase or decrease. Aquarium fish usually sleep for about 8-12 hours.
There are times when fish do not sleep at all. Some fish species do not sleep for a certain period of time in order to protect their young. Migrating fish also do not sleep during this process. Tilapia< It has been observed that fish species such as /u> do not sleep at all until they are 5-6 months old. Studies have shown that it is not clear whether blind cave fish sleep because they live in a constantly dark environment.
Do Fish Feel Pain and Stress If They Can't Sleep?
Fish, like other creatures, can feel pain and experience stress. This also applies when they can't sleep. In studies conducted on Zebra Danio fish, it was found that those who were deprived of sleep for a few days with a mild electric current slept more when this situation returned to normal.
It was also understood that they slept normally when a dark night environment was provided after being kept in constant light for a few days, disrupting the day and night cycle.
