Do Goldfish Sleep? Facts to Know And Mistakes to Avoid

Do Goldfish Sleep? Facts to Know And Mistakes to Avoid

Yes, goldfish sleep, but they do not lie down to sleep as most mammal animals do. Instead, they slow down, stay in place, and move gently to maintain stability. They can sleep for up to 12 hours a day and will serenely float just over the bottom of their aquarium. They have no eyelids; thus, they cannot close their eyes. They often float close to the bottom of the tank or pond, about an inch above it, with their heads inclined slightly downward.

While they are resting, their color may somewhat fade; when they are awake, it will return to normal. When they are sleeping, they use color change as a safety strategy to protect themselves from predators. Finally, unlike humans, goldfish do not experience periods of deep, REM sleep nor do their brainwaves shift throughout sleep.

It would be a good idea to incorporate light in your aquarium if your tank is in a low-light spot or if you wish to cultivate live plants, like hornwort. Remember to turn off the aquarium light at night to mimic the natural cycle of day and night. Goldfish love to sleep in the dark, just like people do.

How do goldfish sleep?

As I said above fish don’t sleep as we do or even like mammals’ animals. Goldfish can’t physically close their eyes, because they don’t have eyelids. The way goldfish sleep or relax moves very slightly in a specific area of the tank while maintaining their balance. Goldfish frequently take a nap lower in the tank, close to aquarium accents.

Remember not to leave your aquarium light on for more than 12 hours a day if you have one. This will stress out your fish. You may be asking what a stressed goldfish looks like?

Your fish may be extremely stressed if he is swimming rapidly in circles, smashing to the bottom of his tank, rubbing himself against the gravel or rocks, or locking his fins at his side.

Here is another question many fishkeepers also ask: Can goldfish see in the dark? For this question, I wrote an entire post check it out by clicking the link.

How to tell if your goldfish is sleeping or sick?

Fish usually lie motionless at the bottom of the water or very near the water’s surface when they are sleeping, which makes it quite simple to identify. They react slowly or sometimes not at all to what is going on around them. They breathe quite slowly, as you can see if you observe their gills.

If your goldfish is sick, you’ll notice the following signs:

  • Loss of appetite
  • slowness
  • Loss of equilibrium or control over buoyancy, floating on one’s back or “sitting” on the tank floor
  • Shimmying or swimming erratically or spirally


Goldfish need sleep just like people and other animals. Fish require sleep to recover their energy and maintain healthy immune systems. They lose their ability to fight off illnesses and their metabolism slows down if they don’t get enough sleep.

The fish determines how much rest they require. While some goldfish take an afternoon sleep, others are awake until nightfall. Fish need exposure to normal day and night cycles in order to get appropriate rest and be healthy.