Do Goldfish Sleep

By Jitendra Kathe from

The Goldfish is an extremely popular spectacular fish, with many fun antics, that is a hardy cold freshwater fish breed. Goldfish are an excellent choice of fish for beginners, and they can be kept outside in a pond or inside in a tank, with very little fuss.

As a Goldfish owner, you may have wondered whether they ever sleep, and how they essentially sleep, as they do not lie down or float or show any form of sleeping habit.

Well, not just this, but did you know that Goldfish do not have eyelids, so they cannot sleep as we do, yet in turn yes, they do sleep, just not as we would imagine.

Goldfish have an interesting way of sleeping, and you can also train them according to a sleep schedule, so let us look a bit further into Goldfish sleeping habits.

Goldfish Sleeping and Feeding Times

According to many studies done on different fish species, Goldfish are Nocturnal and Diurnal, and in some cases even Crepuscular, which means they vary in the phases of their daily activities, inactivity, and thus in their sleep routine.

Some individual Goldfish may be diurnal, while others are nocturnal depending on the personality of the fish, or when food is available. However, Nocturnal behavior in Goldfish is more related to their natural habitat.

Goldfish, in general, will sleep when food is less available, and be more awake and active when food is available, or expected. In nature, predators also play a large role in the phases in which goldfish are awake or asleep.

In some cases, it is said that they can be:

Diurnal – Diurnal means that the Goldfish will be most active during the day, and sleep at night.

Crepuscular – Though there is very little evidence of Goldfish being Crepuscular, this means they are active early mornings, and late afternoons, dusk and dawn.

Nocturnal – Nocturnal means that they are active at night, and will sleep, or just be less active during the day, which is also not very likely in most captivity bred Goldfish.

Thus, as concluded by studies in “How Fish Behave” Goldfish will adapt to a daily phasing of sleeping and activity that will give them maximum access to foraging, and food availability.
do goldfish sleep

How Light Affects Goldfish

Whether your Goldfish are Diurnal, Nocturnal, or Crepuscular in behavior, and whether you feed during the day or night, they do need a clear indication of daytime and nighttime. Keeping your Goldfish in well-lit conditions, as they would be in their natural environment, is crucial. The tank should not be in direct sunlight but should get either indirect light, or have a tank light. The light will help to give your Goldfish a more natural schedule.

On the other hand, when you look at Goldfish care in general for any species of Goldfish, they do need light, especially if there are live plants inside the tank, which will need light for photosynthesis. Though, direct sunlight could be detrimental for your Goldfish and does cause an increase in the growth of algae. Direct sunlight can also increase the temperature of the water in your Goldfish tank, which may not be good for their health, as they prefer cold water.

How Goldfish Sleep

Goldfish unlike most animals and people do not tuck themselves away and lie down when they sleep.

Goldfish will just become much less active and stay in a single place, moving slowly to help keep themselves more stable. They will mostly drift low in the water just an inch or so away from the bottom of the tank, or pond.

They have an instinct to change or fade their color when they sleep, as a safety measure against predators.

According to studies done, there are no changes in the brainwaves of Goldfish when they sleep, so they do not enter into a REM stage or other stages of sleep such as most humans and animals do.
how do goldfish sleep

When Will They Sleep

Naturally, Goldfish will sleep depending on the availability of food and foraging, however, they do sleep better in a dark and quiet environment.

Noise and sudden light may startle your Goldfish, so it’s best to keep them in an area where it’s quiet and where the light will stay off for the whole night.

At the same time, you can ideally train your Goldfish to sleep using a light in the tank, and turn it on and off at the same time every day. The light in the tank should not be on longer than 12 hours during the day, as Goldfish do need more rest.

Sometimes you may even notice that when it’s not dark enough, your Goldfish will seek out plants and hideouts in their tank to provide some darkness and shelter for sleeping.

Do They Need To Sleep

Though Goldfish do not fall into a deep sleep, they still need rest to keep their immune system strong, and to keep up their energy reserves.

Goldfish that do not get enough rest can become more prone to infections and have a slower metabolism that could cause digestive issues.

Most Goldfish will take a short nap during the day, and sleep at night, or they may just sleep at night, it all depends on the individual needs of the Goldfish.

Thus, to keep your Goldfish happy, healthy, and energetic, with a healthy metabolism and eating habits, they should be well rested.

A good schedule for your Goldfish, sticking to times for feeding, sleeping, and waking up will also create a calmer environment for them, and help to prevent them from becoming stressed, as they know what to expect during their daily cycle.
keep goldfish happy

How to Distinguish Between a Sleeping Goldfish and a Sick Goldfish

Now, the issue comes in whether your Goldfish is sleeping, or sick. Many individuals have mistaken a sick Goldfish for a tired or sleeping Goldfish. So according to Dr. Hess, a Qualified Veterinarian and Specialist in Fish and other Animals, you should always be alert for these signs in your Goldfish to distinguish between sleeping, illness, and distress.

1. Goldfish Sleep Upright – When Goldfish sleep, they will remain stationary, but in an upright position with their head pointed slightly downward. They should not turn sideways or upside down, or lie down at the bottom of the tank.

2. Goldfish Do Not Lie On Their Side – If your Goldfish is lying down on its side, it may indicate a bacterial infection, caused by high concentrations of ammonia or nitrites in your tank.

3. Goldfish Do Not Float Upside Down – A Goldfish floating upside down is a very bad sign, meaning there is a bacterial infection or that the Goldfish most likely has Swim Bladder.

Consulting with a veterinarian on the behavior of your Goldfish, and for treatment will be a good choice, as they can prescribe medication, or give you the best advice.

How a Healthy Goldfish Will Appear Sleeping

A healthy sleeping Goldfish will show the following signs when sleeping;

  • The Goldfish may seek out a dark and slightly hidden spot between plants or décor at the bottom of the tank rather than the top or middle.
  • They will usually remain stationary, with very small, slight movements to enable them to stay stable and in a fixed position.
  • Goldfish sleep in a completely upright position and will never tilt to their side, float upside down, or lie down in any way.
  • They may tilt their heads downward slightly when sleeping. Goldfish do not have eyelids, so they will sleep with their eyes open.
  • Your Goldfish may change color, becoming pale and slightly less bright, which is just a defense mechanism against predators, as we have mentioned before.

goldfish sleeping

To Conclude

A healthy Goldfish will hover just above the tank floor and may change color, looking slightly paler when they want to nap. Turning off the lights, and keeping noise levels low, will help your Goldfish enjoy a healthy, and peaceful nap. A well-rested Goldfish will be energetic, have a good metabolism, and be more healthy in general.

Frequently Asked Questions

Why Do Goldfish Yawn?

You may have noticed your Goldfish yawning. Well, this is not intentionally a yawn, but rather your Goldfish clearing out its gills with water. So, if you think your Goldfish is trying to indicate sleepiness by yawning, it is completely not true.

How Do I Teach My Goldfish to Sleep?

You can establish a sleeping pattern with your Goldfish by adapting feeding times to during the day, and switching off the lights, and noises to create a dark and quiet atmosphere for your Goldfish to sleep. Keep in mind that some Goldfish also like to take an afternoon power nap.
Having some shelter such as plants, caves, driftwood, and other tank decorations will in turn create a safe space for them to sleep more peacefully, feeling less threatened.

How Long Do Goldfish Sleep?

Goldfish need between 8–12 hours of sleep a day. They may take a long nap at night, and sleep in short cycles during the day.

More tips about goldfish: How long do goldfish live?

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