Do Fish Sleep? How Do Fish Sleep with Their Eyes Open?

Do fish sleep? You must have seen other animals while sleeping, but have you ever seen a fish being asleep? So the answer is, it depends on the fishes, such as fish species. If we talk about dolphins, they have such a special property that half their brain sleeps and half remains awake. This is because dolphins sleep very differently from the way we humans do. The reason is they have to remain alert or conscious, even when they are asleep, as their breathing is not automatic, and so they have to control it consciously. If dolphins ever went into deep unconscious sleep as we do, surely they would stop breathing and die or drown eventually. 

In other words, Dolphins allow only half of their brains to sleep at a time and the other half remain alert so that they can breathe and see threats in the environment. This kind of sleep is generally known as unihemispheric sleep as the sleep occurs in only one brain hemisphere, while the other hemisphere remains active or alert. This means they remain in a cycle and continue to make body movements constantly even while sleeping. 

Most of the normal fish remain still in one place while resting or sleeping, those who have an aquarium in their home will know this fact clearly. During this period, their breathing and metabolic rate get reduced, brain activities slow down and even they no longer have eyelids to close, which could make them appear asleep. Now the question arises that if they have no eyelids and their eyes are open, are they still sleeping? The clear answer is yes. Because scientists have measured the activity of their brain with the help of many devices on the graph. Detection was done in such a way that when they were not sleeping some movement was visible on the graph and when they were in deep sleep there was no movement or very little movement on the graph. 

It is also acquired by the study that they also have a sleep schedule as they can sleep at any time during the day or night, even though the absence of eyelids showing as if they are not sleeping. But the mysterious fact is that there are many fishes that according to scientists are very deep inside the ocean and they never sleep. 

Maybe there are many such mysterious species in the ocean, but they have not been able to be explored properly, because even though humans have set their feet on the moon and are ready to set even on mars, but they are only succeeded in exploring only a little fraction of the entire oceans and the remaining 95 percent is still pending.