Do Koi Carp Sleep? When | How Long?

Have you ever wondered if the koi carp in your pond ever go to sleep? Do they sleep at night like humans or are they nocturnal? So do koi fish sleep?

Usually, koi do their sleeping in short spurts and go somewhat dormant during the winter, which is when they do most of their sleeping. They don’t sleep for 8 hours as you do, but they do have to rest from time to time.

do koi carp sleep

What Do Koi Do at Night?

At night, koi will generally take some time to rest. They subtly float in a single spot while they’re asleep, usually in a group at one time. You might not see this, as koi tend to choose the bottom of the pond to sleep.

They do prefer sleeping at night, but if your koi happen to be awake, then there is usually a simple answer. For example, it could be that your fish are staying up at night because that’s when the best food sources like insects are more active.

On the opposite side of things, there could be something lurking around at night (such as a raccoon or cat) that is scaring or even hunting your koi fish. After all, who could sleep with something around that wants to eat you?

Unless you want to stay up and do a stakeout of your pond, you’ll want to search the area surrounding your pond for tracks to find out if that really is the case.

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Are Koi More Active at Night?

While koi fish are more likely to sleep at night, but it’s not unusual for them to be active at this time. They generally prefer sleeping at night, but like any adaptable animal, they will change this routine if they’re hungry or scared.

Koi are more active during the day, sleeping at night when the sky is dark, and the water temperature has dropped. However, there could be a couple of things keeping your fish up at night. As we’ve discussed there are usually two reasons your fish are awake at night:

  • Eating bugs
  • Hiding from predators (or watching for danger)

If this isn’t the issue and your koi are still sleeping during the day, this could mean a few things that include:

  • Sickness or Parasites
  • Lack of Oxygen
  • Poor Water Quality

Since fish don’t have the same sleep requirements as humans, they can easily skip out on sleep and make it up later, if needed. A fish will only sleep for a couple of hours at a time, so it’s nothing for them to miss it for the opportunity to eat.

Do Koi Fish Sleep on Their Sides?

No healthy fish should ever be on their side, whether they’re awake or asleep. Koi fish sleep in an upright position, stably floating in a single spot, and it’s usually undetectable. So, if one of your koi fish is laying on its side, it’s very likely sick or dying.

This may look odd to you if you do see it, but it’s totally normal for a sleeping koi to remain in one spot for a while. They also sleep in groups, which is necessary for safety measures. Even weirder, since they lack eyelids, they also sleep with their eyes wide open.

Koi, and many other fish, will only lay on their sides when they are seriously ill. Alternatively, a dead fish may also float on its side for a time before rising to the surface belly up.

If your fish does not move after a long time, it may mean that it’s been affected by illness. Sleeping sickness can also affect koi, displaying itself with oversleeping and extreme lethargy.

Do Koi Fish Need Darkness?

As predominantly outdoor fish, koi really don’t need any more light or darkness than the sky already provides. This means you won’t need to add any light or shade unless it’s to protect your pond from the sun.

Indeed, your koi usually won’t need to be in the dark. Any darkness they need during the daytime is provided at the depths or in a shady spot in your pond. This is the same with many pond fish, including most species of carp like goldfish and koi.

Of course, there is one exception koi fish not needing light. When koi are kept in tanks, they will need to have special UV lights during the day. The UV rays help keep them healthy, as well as vibrantly colored.

As a side note, it’s very important that your pond is not in direct sunlight. The sun and warmer water promote algae growth, which will destroy the pond’s water quality in the long run.