Do Fish Sleep?

Before I start answering the question, do fish sleep, let us understand what the term sleep implies. According to the Merriam-Webster dictionary, sleep is, 'the natural periodic suspension of consciousness during which the powers of the body are restored.' In simple terms sleep is a state of utter relaxation, where there is temporary cessation of thoughts and ideas, and the strength of the body gets restored. Now that we know what sleep is, let us discuss if fish sleep or not...

Fish and Sleep
Yes, fish do sleep, if you agree with the above definition of sleep. As you can see in the picture, the dolphin is stationary and resting, and thus can be called sleeping. Most fishes do not have eyelids, other than sharks. Some fishes in the deep ocean never stop moving, but some of the fishes are almost always nearly motionless. Some are active during the day and rest at night. So we can conclude that yes, most fish do sleep or rest in a condition where their minds go blank and is devoid of any thoughts or ideas. When some species of fishes are resting, they will just float at a particular place, while some others take shelter in a particular spot, like in the mud or coral. Some of the fishes even build a nest for resting! These fishes remain alert for any sign of danger, but at the same time are able to rest peacefully, somewhat similar to cats. Here are some more interesting facts on sleeping habits of different animals, which are pretty amusing.

Amazing Facts on Sleeping Habits of Animals
Below are some interesting facts on sleeping habits of different animals.

• Cockroaches sleep for a period of 14 hours, if they are deprived of this, then they makeup for their sleeping hours the next day!
• Snakes sleep with their eyes open, as they don't have any eyelids!
• Elephants stand during their non-REM sleep, but will lie down for their REM sleep (sleeping stage where dreams occur).
• Crocodiles sleep with their mouths open.
• Large animals like lions which are carnivorous and feed on other animals can afford to sleep for long periods (as much as 17 hours), because they are rarely in danger.
• Birds dream about singing, while they are asleep!
• Albatrosses can sleep while they are flying.
• Some animals can tuck themselves even in a bed of cold snow.
• A red fox is warm and snuggles in its own fuzzy coat blanket.
• A snail, on an average, can sleep for a period of 3 years!
• A koala can sleep up to 22 hours in a day, which is almost the whole day!
• On the other hand, a giraffe sleeps for less than 2 hours in a day!
• Another lazy sleeping animal is the sloth, which sleeps for around 20 hours of the day!

Every animal needs a period of rest and as mentioned about some lazy animals like koala bears and sloths sleep for 20 hours in a day, while animals like giraffes sleep only for 2 hours (even we humans get to sleep more!). Sleep is extremely important because every living being, including humans are active and need some rest period to restore the powers of the body. The same holds true for fishes. So, I hope I have cleared your doubts on the matter of do fish sleep.