Most fish do not have eyelids, so they cannot close their eyes. But does this mean that they are not sleeping? The question of whether the fish sleep, it is easy to confuse even an experienced aquarium owner, not like an ordinary person. Most often this moment interests children, curious why. So how do fish sleep and do they sleep at all?
Oh these stereotypes
A person is accustomed to having to close his eyes for sleeping. So do animals. It is advisable to be in the dark in a lying, relaxed position, although overworked people simply “turn off” in any position. But to sleep with your eyes open is extremely difficult to imagine. Therefore, the thinking stereotype works: if it is impossible to close the eyes, then such a creature cannot sleep.
However, the inhabitants of the underwater world is not so. Eyelids for people and animals are needed in order to protect the eyeball from drying out. Fish are in the water, so this danger for them simply does not exist. Water moisturizes and cleans the eyes of these creatures.
How do fish sleep?
One can understand that the fish has fallen asleep by the following signs: it froze in the thickets or other secluded place, hung in the water column. Some may even lie down, and some species prefer to relax on their side.
Most species of fish prefer to sleep in the dark, so if you come to the aquarium and turn on the light, you will be able to notice how its inhabitants return to their awake state, waking up. But there are those who rest during the day. These are predator fish, for example, catfish.
However, fish dream is not the condition that is meant by this word in humans. How do fish sleep? For them, this is not a state of complete relaxation and unconsciousness, as we do with you, but rather a process of slowing down the functions of vital activity. This allows the fish to quickly become active, if something dangerous or edible has arisen nearby.
The phase of deep sleep, in which there is almost complete loss of contact with reality, is absent in fish. However, during sleep, there is a recovery in the work of the nervous system and other body functions.
Do all fish sleep the same?
Hang in the water column and drift during sleep can only fish that are of the type of bone. They manage to do this due to 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 tank. The smaller it is, the deeper it will sink into the water column. Most residents of home aquariums refers to the bone.
Ramps and sharks are cartilaginous fish, they have no swim bladder. How do fish sleep if they can’t hang in the water? They are laid on the bottom or rest while driving. Antsistrusy and fights are considered cartilage fish suitable for keeping in an aquarium.
There are some underwater inhabitants who need to hide in a cave for sleeping. Parrot-fishes are sleeping very unusually. practically under a blanket. Only as it they use mucus, which is released by the fish through the mouth. The mucus envelops the carcass, creating a protective cocoon in which you can safely rest and not be afraid of anything. In the morning, the fish leaves their “blanket”.
Why do you need to know about the features of sleep in fish?
As the fish sleep, it is important to know not only to satisfy their own curiosity, but also in order to provide the fish with comfortable living conditions. Like people, they do not like, if they violate their regime, they may suffer from insomnia, therefore:
- be sure to turn off the light in the aquarium at night;
- pick up the fish so that they sleep at one time of day.
There are species of fish that sleep during the day and prefer thickets for this. If you put these in your tank, during the day it will look empty and uninteresting.