Many people think that fish never sleeps because they live in water.

In fact, fish also sleep and need rest. But indeed the way to sleep is different from most humans and animals.

Fish don't have eyelids except sharks. Therefore, if you look at it, it will be difficult to tell which fish is sleeping and what is not sleeping because the eyes are always open.

The way the fish rests is with semi-conscious sleep and does not fall asleep, even he can still move his tail to ensure the flow of water is maintained towards his gills. This is done so as not to lack oxygen.

Fish that sleep also must always be aware of any threat of danger or other fish attacks that can make it hurt or die.

Fish fall asleep with the body floating in the water, besides that fish that are in the sea will deliberately hide behind coral reefs so as not to be seen by their predators.

Some other fish sleep by pretending like dead fish and lying on the bottom of water.

Large fish like sharks will make a slow swimming motion as they sleep without closing their eyes.

Besides Fish, the Way Dolphins Sleep is also Unique, Even though living in water, dolphins and whales are mammals that breathe with the lungs just like us.

To get oxygen, dolphins must jump out of the water periodically. That's why we often see dolphins jumping out of the water like they're playing. Even though they do it to breathe. The way to sleep is similar, that is, with a semi-conscious condition. The difference is, the body of a dolphin does not stay in place and does not float but continues to move actively as if it is not sleeping.

It turned out that the dolphins were sleeping, not their bodies. Dolphins will sleep half their brain every session alternately, every four hours.

If the right brain is sleeping, the left eye will open. Likewise if his left brain is sleeping, his right eye will open. This is done by dolphins to be able to breathe smoothly and to guard against predator attacks that suddenly come.