Why Do My Koi Flash At Night?

Koi are a species of freshwater fish that are popular in both Japan and the Western world. They are often kept in ponds or aquariums, and are known for their brightly colored scales.

Koi are known to be friendly fish, and will often approach humans who are near their pond.

One behavior that koi are known for is flashing. Flashing is when a koi swims rapidly up to the surface of the water and then back down again.

This behavior is most often seen at night, which has led to some speculation as to why koi flash.

There are a few theories as to why koi flash. One theory is that koi are trying to attract mates.

Another theory is that koi flash in order to scare off predators. However, the most likely explanation is that koi flash in order to increase oxygen levels in their blood.

Whatever the reason, koi flashing is a fascinating behavior to observe. If you have koi in your pond, be sure to keep an eye out for this behavior at night!

Why do my pond fish keep flicking?

The most common cause of fish flicking is a build-up of waste products in the fish’s water environment. This waste can come from the fish’s food, from the fish’s body, or from the fish’s breathing.

When the waste products build up to a certain level, the fish start to flick their fins to create a current that moves the waste away from them.

What do koi do at night?

Koi, as all fish, need to rest at night. Fish swim in open water during the day and rest at night.

Koi, like other fish, have a built-in clock that tells them when it is time to rest. When it is time to rest, they close their eyes and stop moving.

How do I know if my koi is stressed?

One way to determine if your koi is stressed is to look for behavioral changes, like decreased activity, erratic feeding, and hiding. Additionally, you can check the water quality and pH levels to see if they’re off.

If you notice any of these changes, it may be time to take your koi into care.

What does koi flashing look like?

When a Koi is swimming, their scales will sometimes flash in a quick succession. This is most often seen when the Koi is startled or when it is trying to escape a predator.

What does it mean when a koi flashes?

When a koi flashes, it means that the fish is excited or stressed. When a koi flashes its colors, it is usually a sign that the fish is feeling threatened or angry.

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Does flashing always mean ich?

Flashing may always mean ich in some cases but not always. Flashing may also mean other things such as an obstruction in the intestines.

The best way to determine if flashing means ich is to perform a thorough examination of the fish.

Do koi like light at night?

Koi do not typically like light at night. This is due to their natural tendency to retreat into the shadows to avoid predators.

This can be exacerbated by artificial light, which can confuse the fish and cause them to swim into dangerous areas.

How do you put koi to sleep?

Koi ponds can be very peaceful and tranquil environments, but if they are not properly taken care of, they can become quite disruptive. One way to put koi to sleep is to lower the water level in the pond to around 1-2 inches and then turn off the lights.

The fish will become disoriented and will eventually fall asleep.

How many hours a day do koi fish sleep?

Koi fish are active fish and typically swim around in their aquariums or ponds during the day. They will typically go to bed at night and will sleep for about 8 to 10 hours.

How do you calm down koi?

There are a few ways to calm down koi. One is to feed them a lot.

Another is to put them in a calm environment. Another is to use a calming agent.

Do I need to add salt to koi pond?

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Salt is not necessary for koi ponds, but it can be beneficial. Adding salt to a pond will help to keep the water clean and reduce the risk of algae blooms.

How often should you feed koi?

Koi are herbivores, so they should be fed a vegetarian diet of flakes, pellets, or water with a few vegetable pieces mixed in every day.


There are a few reasons why your koi may be flashing at night. One reason could be that they are trying to remove parasites from their skin.

Another reason could be that the water temperature has dropped and they are trying to raise their body temperature. Lastly, koi are social creatures and they may be flashing as a way to communicate with other koi in the pond.