Do Goldfish Sleep? (How To Tell And Patterns)

Have you ever wondered whether your pet goldfish sleeps? You can go up to your goldfish tank at any time of day or night and see your pet with its eyes wide open. So how do your goldfish rest? The fact is that goldfish do sleep, but there’s a lot more to learn, so read along to learn all about your goldfish’s sleeping habits!

Key Takeaways

  • Goldfish do, in fact, sleep. Fish can enter deep sleep at night
  • A resting goldfish and a sick goldfish are two different things. Learn about the differing behaviors
  • Incorrect parameters can lead to a fish resting or getting sick. Keep your parameters in check and monitor them

How Do Goldfish Sleep?

Goldfish might not tuck themselves under the covers each night, but they certainly do sleep! However, fish don’t sleep in the same way that you and I do. When goldfish sleep, their metabolism slows, and they become inactive. Research has shown that fish can enter deep sleep at night1.

Until recently, fish were not thought to exhibit rapid eye movement or REM sleep like ourselves and other mammals. However, scientists have discovered that zebra danios enter a pretty similar state. We don’t know if danios or other fish like goldfish dream, but it’s certainly possible.

Goldfish sleep at the bottom of their tank to feel safer from predators. You might also find them sleeping between live plants or aquarium decorations where they can stay more still and feel secure.

Why Do They Sleep?

All that swimming and exploring in your aquarium certainly tires out your goldfish, so they need to rest regularly to stay healthy.


Goldfish don’t fall asleep like people each night, but they get most of their rest when it’s dark. That’s why providing your goldfish with a natural day and night cycle is important.

What is a fancy goldfish

Running your aquarium lights all day and night can result in a sleep-deprived goldfish, so be sure to switch off the tank lights for at least twelve hours a day. Keeping your lights on for 6 to 8 hours a day is recommended because more than that can cause algae issues.

The best way to keep things regular in your tank is to set your aquarium lights on a timer. That way you won’t forget to switch the lights on or off.

Goldfish are sensitive to loud noises and sudden movements when they sleep at night. High noise levels will disturb your fish’s sleep schedule, so never put speakers or televisions next to your goldfish tank.

How Long?

Goldfish can sleep for short periods or for many hours at a time. Some goldfish nap during the day, while others sleep at night. Creating regular light and dark periods each day will allow your goldfish to develop its own natural sleeping pattern and get enough sleep.

Some goldfish owners report that their pets go to sleep in the same spot each night and are still there each morning. The important thing is to let your goldfish rest each day in a dark and quiet environment.

If your goldfish is not getting enough rest, it could cause stress and weaken its immune system in the long run.

Why Don’t Fish Close Their Eyes?

The simple answer to this common goldfish question is that fish don’t have eyelids. Eyelids are very useful for keeping our eyes moist and free of dust and other irritating particles. This isn’t a problem underwater, so goldfish don’t need to blink!

Is My Fish Sleeping Or Sick?

Many new goldfish owners are surprised to learn that their fish sleep, and it can be pretty worrying to see your pet sleeping motionless for long periods. However, you can rest assured that this behavior is completely normal.

However, goldfish can get sick with conditions like swim bladder disease from time to time, so it’s good to know if your goldfish is sleeping or showing signs of poor health.

Read on to learn what to look out for.

Signs Your Goldfish Is Sick

  • Seeing your goldfish sleep upside down or leaning to one side could indicate swim bladder problems. Swim bladder disorder is a common illness among goldfish and other pet fish. This condition causes buoyancy issues which can make your fish sink, float, or swim erratically.
  • Cloudy eyes, sores, or a white film over the body are often signs of a bacterial infection.
  • Missing scales, white spots, and scratching against the substrate are common signs of parasites.
  • Rapid breathing is a clear sign of stress, which can cause illness in your goldfish. Poor water quality, drastic water temperature changes, and disease can cause this common symptom. Rapid breathing can also result from low oxygen levels. Running an air pump and airstone can be helpful.

Signs Your Fish Are Sleeping

  • Your goldfish is sleeping if it’s stationary at the bottom of the tank or hovering about an inch above the substrate. Most healthy goldfish rest at night when it’s dark, but you might find your goldfish sleeping any time.
  • Sleeping goldfish often tilt their head downward slightly but keep their body upright.
  • Your goldfish’s color might be a little dull when it is sleeping. This can help your fish hide from predators.
  • Sleeping fish can breathe without swimming. They gulp water to maintain a constant flow through their gills.

What To Do If They Are Sick

Accurately diagnosing illnesses in freshwater fish can be tricky, but you can often find the cause of your fish’s health problems, and there’s a good chance that you can treat your pet at home.

Fish get sick when they are under stress, and stress is often caused by bad environmental conditions. What does that mean? Well, your fish need clean, healthy tank water at the right temperature.

  • Test your water quality

Goldfish are pretty messy fish, so they need good filtration and a tank of at least 30 gallons to stay healthy. Your water quality can become dangerous if you don’t cycle your aquarium and perform regular water changes.

Your water should contain no traces of ammonia or nitrite. Nitrates can harm goldfish in high concentrations, so keep them below 40 ppm. A level of 20 ppm or less is ideal for long-term care.

  • Check your water temperature

Goldfish are coldwater fish that prefer a lower temperature range than most other fish. They should be kept in water temperatures between 68 and 74°F. Tropical fish tank water temperatures will harm your goldfish in the long run.

Aquarium heaters are adjustable, and they do show the water temperature. However, these readings can be pretty inaccurate. I recommend getting a thermometer so you can monitor your water temperature easily.

Digital thermometers with built-in alarms are great for this purpose. These handy machines let you know if the water gets too hot or cold for your goldfish.

  • Other Parameters

Poor water quality with high ammonia levels and high water temperature are common causes of stress, but goldfish also have other preferred water parameters. Aim for the following readings:

  • pH: 7 – 8.4
  • gH: 100 – 300 ppm
  • KH: 50 – 120 ppm

You can test these parameters with a master test kit. Any inconsistencies can cause stress on your goldfish and will need to be addressed as soon as possible.


Providing correct treatments for your goldfish can mean the differences between live and dead fish. Goldfish are susceptible to many illnesses, and it’s not always the fishkeeper’s fault when things go wrong.

Let’s look at some things you can do to help a sick goldfish.

  • Move the sick fish into a quarantine tank

A quarantine tank is a small tank where you can administer treatments to your sick goldfish without affecting your other fish or aquatic animals. Your quarantine tank should hold at least a few gallons of water and have its own filter.

Test the water before moving your fish. If the water in your main tank is the problem, you’ll need to use fresh, dechlorinated water instead.

  • Observe Your Goldfish

If your fish is not in obvious danger, observe it for a few days and give it a chance to recover. Starting an immediate treatment is not always necessary.

  • Treatment

If your goldfish is in obvious distress or not improving, contact your vet and ask for advice.
There are some excellent fish medications available that you can administer yourself at home.

Condition-specific medicines are highly effective, but you can also treat several common fish illnesses with aquarium salt.


Do The Sleep With Their Eyes Open?

Goldfish cannot close their eyes because they do not have any eyelids. This means they have no choice but to sleep with their eyes open.

Do Goldfish Recognize Their Owners?

Goldfish do have the ability to recognize their owners. It has been proven that some fish can recognize human faces, which probably explains why your goldfish might recognize you but fear other people.

Do Goldfish Need Light At Night?

Goldfish do not need light at night. Goldfish naturally sleep at night in nature when the only light comes from the stars and the moon. You can keep your aquarium lights on for a few hours in the evening to enjoy your fish, but make sure the lights go off for the rest of the night.

How Many Hours Do They Sleep?

Goldfish sleep for 8 to 12 hours per day.

Why Do They Sleep On The Bottom Of The Tank?

Goldfish tend to sleep on the bottom because it helps them hide from predators. There is also much less current at the bottom, so they can relax and sleep without being washed around.

Do They Like It Dark At Night?

Goldfish prefer a natural daylight cycle of light and dark. Keep your tank dark during the day if you like to have your aquarium lights on at night.

Is It Normal For Them To Rest At The Bottom Of The Tank?

Goldfish sleep at, or just above, the bottom of their tank. They may stay on the bottom, sitting still for several hours. However, your goldfish may be sick if it is upside down, on its side, or breathing rapidly.

Final Thoughts

So now you know, goldfish sleep too! Don’t worry if you find your fancy goldfish sleeping. They need their forty winks, too, even if it is technically impossible for them to get any shut-eye.

Have you seen your goldfish sleeping? Tell us about it in the comments below!

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