Do Fish Sleep??

Do fish sleep? And assuming they do, HOW do fish sleep? If you've ever watched fish for any length of time, you know they get plenty of exercise. They're constantly swimming around. It can seem like they never stop. Surely they need some rest from time to time, don't they?

As a matter of fact, they do! If you watch fish long enough, you'll notice that they do take breaks. There are definite periods of time when they seem to hover in place, almost like they're in a trance. But their eyes are open. Are they sleeping?

The simple answer is yes! They are sleeping, and they can sleepat any time during the day or night. Fish do sleep with their eyes open, because they don't have eyelids (except for some sharks) to close!

Fish sleep is not exactly like human sleep, though. For starters, they don't use pillows. They also don't have beds with sheets and blankets! For fish, sleep is more like a resting period similar to a daydream that humans might experience.

If you've ever owned a goldfish or watched one up close, you've probably noticed the times when it's sleeping. It might hovernear the bottom of the tank in a trance-like state. If you put food in the tank during this time, you've probably noticed that it takes longer for the goldfish to respond, just like you might have a hard time waking up from a good night's sleep!

Sometimes people see fish when they're sleeping and assume they're awake because they're still moving. Most fish need to keep moving even when they're sleeping, so that they keep a constant flow of water moving past their gills to maintain a proper oxygen level in their bodies. For some larger fish, like sharks, this can take the form of swimming at a slower rate when sleeping. Smaller fish might be able to do nothing more than occasionally move their fins.