Fish are asleep, they are tired. How do fish sleep?

Most fish do not have eyelids, so they can not close their eyes. But does this mean that they are not sleeping? The question is, whether the fish sleep, it is easy to confound even the experienced owner of the aquarium, not that of an ordinary person. Most often this moment interests children, curious why. So, how do the fish sleep and do they sleep at all?

Oh, these stereotypes

It is customary for a person to close their eyes for sleep. So do animals. It is desirable at the same time to be in the dark in a recumbent, relaxed position, although overworked people simply "turn off" in any position. But to sleep with your eyes open - this is extremely difficult to imagine. Therefore, the stereotype of thinking works: if the eyes can not be closed, then such a creature can not sleep.

However, the inhabitants of the underwater world is not at all so. People and animals need their eyelids to protect the eyeball from drying out. The fish are in the water, so there is simply no such danger for them . Water moisturizes and cleanses the eyes of these creatures.

How do fish sleep?

To understand that the fish was plunged into a dream, it is possible by the following signs: it froze in a thicket or other secluded place, hovered in the water column. Some can even lie down, and some species prefer to rest on their sides.

Most species of fish prefer to sleep in the dark, so if you go to the aquarium and turn on the light, you will be able to notice how its inhabitants return to a cheerful state, wake up. But there are some who rest during the day. These fish are predators, for example, catfish.

However, a fish sleep is not the state that people mean by this word. How do fish sleep? For them, this is not a state of complete relaxation and unconsciousness, as we have with you, but rather a process of slowing down the functions of life. This allows the fish to activate very quickly, if there is something dangerous or edible nearby.

The phase of deep sleep, in which there is almost complete loss of contact with reality, is absent in fish. Nevertheless, during the sleep, the work of the nervous system and other functions of the body is restored.

Do all the fish sleep equally?

Hanging in the water column and drift during sleep can only fish that are of the type of bone. They do this because of the presence of a swim bladder filled with air. The volume of air in this particular organ determines at what height the fish will be in the aquarium. The smaller it is, the deeper it will dive into the water column. Most residents of domestic aquariums refer to bone.

Rays and sharks are cartilaginous fish, they do not have a swim bladder . How do fish sleep if they can not hang in the water? They fit into the bottom or rest during the movement. Ancistrus and botsia are considered suitable for keeping cartilaginous fish in an aquarium.

There are also such underwater inhabitants who need to hide in a cave for sleep. Very unusually sleeping parrotfishes - almost under the blanket. Only as it, they use slime, which is released by the fish through the mouth. Slime envelops the carcass, creating a protective cocoon, in which you can safely rest and do not be afraid. In the morning the fish leaves its "blanket."

Why do you need to know about the features of sleep in fish?

As fish are asleep, it is important to know not only to satisfy your own curiosity, but also to provide the fish with comfortable living conditions. Like people, they do not like, if they violate their regime, they can suffer from insomnia, therefore:

• Necessarily extinguish the light in the aquarium at night;
• Pick up fish so that they sleep at one time of day.

Please note that there are species of fish that sleep during the day and prefer for this thicket. If you put such in your aquarium, in the daytime it will look empty and uninteresting.