Most animals sometimes sleep. Sleep is important because it helps the body and brain rest. People sleep when they close their eyes, lie still, breathe slowly and have little idea of what is happening around them. Some people sleep very deeply and can hardly wake them up.
Fish do not have eyelids and they do not need to close their eyes despite living in water, and dirt and dust cannot get into their eyes. Despite this, the fish still sleeps. Some fish sleep at night and only wake up at night, others sleep at night and stay awake just like we do.
A fun puffer fish.
It is very easy for us to know when the fish is sleeping. That's when they lie dormant, and often lie at the bottom or near the water. They react very slowly to what happens around them and sometimes there is no reaction. Looking at the gills, you will see them breathing very slowly.
If you have a fish tank at home, you can observe it at night and if you turn off the lights, the fish are less active. If you turn on the lights in the middle of the night, you will find that the fish are almost inactive.
Like humans, fish have a clock in their bodies that tells them when to do things such as meal time, sleep time, for example. So, even if you turn on the lights all night, they still sleep.
Some scientists have studied the sleep of fish living in caves without light. They found that even these fishes had periods of inactivity almost as if they were sleeping. Of course, in these always-dark places, there's no sunrise or sunset to mark the day or night, so the pace of these fishes is often different from the ones that live there. light.
Some fish, such as mackerel and some sharks, must swim continuously without stopping for them to breathe. So it's very likely that only half of their brains will rest at bedtime, just like a dolphin.
Seabass create a mucous membrane covering the body at night. This membrane is a thick sleeping bag that protects them from being attacked by parasites while they are sleeping.
Fish don't need eyelids because dust can't get into their eyes, but fish can still sleep.
Someone once asked whether fish dreamed during sleep. So far, we have not got the correct answer, but in some videos of sleeping octopus, they change color. This may be an indication that they are dreaming about fleeing from a predator or secretly stalking their prey, much like their waking activity.
Believe it or not, scientists are studying fish sleep to help us better understand human sleep. The majority of these studies used seahorses and aimed to understand the effects of sleep deprivation, insomnia and the sleep cycle.
Here is a video of some animals, including fish, when they are sleeping:
How do fish sleep?
According to the Theconversation