How do fish sleep?

Natalya Chekanova
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How do fish sleep?

In nature, a lot of unusual. The animal and plant world is striking in its diversity. The features of some living creatures are also surprising. For example, do you know how fish sleep?

Pisces also need a dream

Owners of aquariums sometimes wonder: does the fish sleep? The question arises for good reason, because no one has seen the fish with their eyes closed. And why? They have nothing to close - the eyelids of the fish are missing.

They do not rest in the same way as is customary in humans, birds and mammals. The dream of fish is rather a rest phase, in which all functions slow down, the body becomes immobile, reactions are weakened. Some fish at the depth do not react to external stimuli (they can be touched, shone with a lantern in the eyes). Others feel the slightest danger.

Many fish become almost immobile while resting. And some (tuna, shark) are constantly in motion, lying down on the water against the stream. If water does not pass through their gills, they may suffocate.

Features of different types of rest

The specifics of the rest of the fish depends on their variety. So, astronotus lie on the bottom or hang upside down.Clown fish stacked on the flank at the bottom of the aquarium. Other species just hang still.

How do fish sleep in nature? Cod - lying, flounder buries in the sand, herring - up the stomach, drifting in a stream of water. Most fish seek out for their nooks and places � among rocks, crevices of rocks, algae and corals.

Not all fish sleep at night. Nocturnal predators (burbot, catfish) prefer daytime sleep. But after a hectic night, a fish with a daytime lifestyle can afford a �quiet hour� during the day.

Dolphins have surpassed all (although these are not fish, but mammals). They hardly sleep. While the hemispheres are resting, their brains are awake alternately so that they can rise to the surface and inhale the air. The rest of the time, both hemispheres work.