Do Fish Move When They Sleep

Do Fish Move When They Sleep?

We always get numerous interesting questions in our inbox regarding fish, but this one question “Do Fish Move When They Sleep ?” made us then twice, and we decided why not answer it. The simple answer to this question is yes, some fish move while sleeping as they need oxygen and food for energy. However, it’s just a reflexive motion that does not affect their health or quality of life most of the time. 

Studies have shown how the brain waves of goldfish were more continuous during periods where there was no stimulus from external stimuli than while awake, proving that goldfish share standard sleep patterns as do humans.

However, much research is still needed on how fish get enough oxygen without movement. Also unknown is if changing habitats affect the type or quality of sleep.

How Do You Know If A Fish Is Sleeping?

Well, we think that you can only know if your fish is sleeping is by observing their behavior. It’s not always easy to tell when they’re fully awake. You can also spot them sleeping because they stop swimming around as much, but this might only happen for short periods, which means they could still very well be dozing rather than sleeping.

Different types of fish also behave differently when they are sleeping. For example, salmon will rest near the bottom, so their bodies do not weaken from lack of use. Cichlids are known to use up lots of energy when hunting prey in the wild, so many will start resting during the day and then resume activity at night once their stomachs have been filled with food. Goldfish also go through periods where they will rest one eye, which mimics human nap. Certain kinds, such as catfish, can sleep with both eyes open at once. As fish do not sleep with their eyes closed as humans do, it can contribute to confusion around their sleeping habits.

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How Do Fish Sleep In Water?

The fish alter the rhythm of their swim pattern to slow down and appear as though they are resting or sleeping. Fish do not always use this tactic when it comes to staying in one place for an extended period, but when moving around the tank, the water slows them down.

A dozing fish will often be seen resting on its side or half-submerged in the water. They may also rest on rocks at the bottom of the tank, which is called lying dormant; however, if there was no current, they could be considered asleep. However, most people may take resting for hiding.

How Long Can A Fish Sleep?

Fish can sleep anywhere from one hour to 16 hours in any 24 hours; however, this depends not on how long they have been awake but rather on their species and age. By observing how long their dorsal fin stays still, scientists can tell that they’re just taking a break from swimming instead of getting shuteye.

In addition, many fish move around even while they appear to be sleeping. Which makes it difficult for an observer to determine whether or why they might have fallen asleep at all. This also makes it hard to say how much time any individual fish spends actually “sleeping.”


Scientists often measure periods of inactivity in fish to determine whether or not they are sleeping, but some fish types do move while sleeping. A fish’s sleep patterns are not as well-studied and do vary by species.

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