Do Goldfish Sleep? How, when and how can you tell?


The answer to the question “do goldfish sleep?” is one of the most common things new goldfish keepers want to know about their fish.

Do goldfish sleep?

The answer is that goldfish do sleep, but not in the same way we do. Goldfish sleep is more like “resting”.

At some point in the day your goldfish will become much less active and hover in one particular part of the aquarium or pond, only moving slightly to keep themselves stable in the water. This behaviour tells you that your goldfish is “sleeping”.

The hovering spot will usually be somewhere near aquarium decorations and lower down in the tank. (To see this for yourself, watch goldfish sleep in this video).

All about goldfish sleep

Do goldfish sleep with their eyes open?

You’ll notice that your goldfish don’t close their eyes when they sleep. This is because they can’t! Goldfish don’t have eyelids, so even when sleeping, their eyes always remain open.

This means that your goldfish is always reasonably alert and will be startled if you make sudden movements near your aquarium or switch on your aquarium light. You should try to avoid startling your goldfish in this way, as such stress is not good for their health.

Do goldfish sleep at night?

Like humans, goldfish sleep better in the dark than in brightly lit rooms. You should therefore ensure that your aquarium light is switched off for at least 12 hours per day.

Goldfish don’t necessarily sleep at night, but they do prefer to sleep when it’s dark. It therefore makes sense for your goldfish to follow a similar pattern to your own day. Switch your light on when you get up in the morning and switch it off no more than 12 hours later, shortly before you go to bed. Let your goldfish sleep when you do!

How do I know when my goldfish is sleeping?

You may notice that your goldfish’s color sometimes fades slightly. Spotting this fade in color – along with noticing that your fish is less active than usual – is how you know that your goldfish is sleeping.

When you notice that your goldfish is asleep you should try to avoid startling it. Don’t make any sudden movements near the aquarium, don’t attempt to feed your goldfish and don’t switch on your aquarium lights.

Do goldfish sleep upside down?! 

Some goldfish keepers see their fish floating upside down (or heavily to one side) and assume that this is normal behaviour or that their goldfish is sleeping. Unfortunately, this is not the case!

If you’ve noticed your goldfish swimming upside down or always leaning to one side then you should research “swim bladder disease”.

“Do Goldfish Sleep?” Summary:

  • Yes, goldfish sleep, but not in the same way we do. Goldfish sleep is more like “resting”
  • Goldfish sleep with their eyes open, because goldfish don’t have eyelids
  • Usually, goldfish sleep in one particular part of the aquarium, only moving slightly to keep themselves stable
  • Goldfish often sleep lower down in the tank, near aquarium decorations
  • If you have an aquarium light then you should not keep it switched on any longer than 12 hours per day
  • When your goldfish sleeps, its color will fade slightly and it won’t move around very much

Read more in our Goldfish Info series! 


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