Do Swordtail Fish Sleep?- You Might Be Interested To Know

Lauren Kiekbusch
Do Swordtail Fish Sleep

Almost every animal sleeps. Sleep is critical for both mind and physical rejuvenation. People sleep by closing their eyes and lying still for long periods. Our breathing slows down as we become less aware of what is going on around us. Some people sleep a lot, and it takes a lot of time and effort to awaken them.

The fish do not have eyelids because dust can’t get into their eyes when they’re underwater. However, fish continue to slumber. Some people are only active during the day and sleep at night. However, others always behave vice versa. 

For those who are curious to know, this article answers the question: do swordtail fish sleep? Again, it discusses the sleeping behaviors of the swordtail fish and its sleep requirements.

Also worth reading;

  1. Why Do Swordtail Fish Eat Their Fry? (All You Need to Know )
  2. Are Swordtail Fish Aggressive?- All You Need To Know
  3. How Long Are Swordtail Fish Pregnant For?
  4. Swordtail Fish Fry Care – How to Care for Baby Swordtails?

Do Swordtail Fish Sleep?

The swordtail fish sleep, but their sleeping habits are quite different from those of humans or mammals. Eyelids are absent in swordtails. I have to look at their conduct as well as their physique to answer the question.

Fish are not exempt from the exact requirements of terrestrial mammals regarding sleep and rest.

Swordtails do sleep, but not in the same way that humans and other animals do. Even while the sleep patterns of fish vary greatly, each animal sleeps uniquely. Most animals require some downtime to recover and slow down their bodily functions.

According to the dictionary definition of sleep, the swordtails do not have a perfect description of sleep. However, they have a time in which they slow down to be inactive, and that is what we call sleep in a swordtail fish. During this period, the fish’s heartbeat and movement slows down.

The two indications should indicate that the swordtails’ metabolic rate has slowed to conserve energy. The researchers in the study I just discussed used a combination of characteristics to explain sleep. The following are some of the factors:

  1. The sleeping posture of species, such as lying down in humans or caving in the case of some fish species.
  2. The preservation of behavioral quiescence, such as slowing down or inactivity
  3. It gets more challenging to stimulate them.
  4. It is possible to wake up from a state of slumber. To put it another way, they are readily roused.

The Sleeping Behavior Of The Swordtail Fish

If you have swordtails in your aquarium, you already know that they are always swimming except when stressed, sick, or resting.

Just as you expect with the other animals, swordtails will tire after swimming throughout the day, and they will stop moving entirely or sleep to rest.

Sleeping gives the body a chance to replenish its energy and relax naturally. Swordtails’ mobile nature burns a lot of energy, especially when swimming; therefore, they need to sleep to replenish the energy they need to keep moving.

If a swordtail does not receive enough sleep, its body will become increasingly unsettled, similar to a human’s.

Swordtails sleep for various reasons, the most common of which is to regenerate body energy or rest. They use their eyes for multiple tasks, including concealing, hunting for food, and swimming around the aquarium tank.

Because sea waves impair their sense of smell, they must rely only on their vision. In simple terms, the swordtail must depend more on its eyes to stay afloat. As a result, they require some time to rest and sleep. The swordtails can keep swimming if they have adequate sleep.

Swordtail fish – the ones you maintain in your aquarium tank – have a sleeping cycle influenced by the interior lighting. During the day, the fish are active, and at night, they sleep. Light is the decisive factor of day and night inside the aquarium tank for your swordtails.

Your swordtails will begin to demonstrate sleepy behavior if the surrounding environment is dark. So, if you leave your fish in the dark for a few minutes, you’ll probably discover them sleeping.

The swordtails will rest at intervals if you live in the light both day and night, but they will not rest peacefully.

To allow the swordtails to rest and sleep, set the aquarium tank environment to dark for some time. Failure to do so will cause the fish to become stressed due to insufficient quality sleep.

Signs That Show That The Swordtail Fish Is Asleep

Below are ways you can know that your swordtail fish is fast asleep;

  • Inactivity for long periods
  • The fish swims to the aquarium tank’s surface or bottom.
  • Gills with slowed breathing
  • Response time to external stimuli is slower.
  • Sleeping patterns, such as time and position, should be followed regularly.

Sleep Requirements Of A Swordtail Fish

Swordtails sleep, and they require sleep to have a healthy existence. However, because their sleeping habits are so dissimilar from ours, you’ll have to pay closer attention to determine whether they’re sleeping or simply worried or sick.

If you own a swordtail, you must ensure that they have all of their sleeping necessities and that the room is dark when they are asleep. You’ll have to make the room dark frequently to conserve more energy, which they need to swim around all day. Make sure the aquarium’s water is in good shape and add more live plants.

When The Lights Are Turned On, Can Swordtails Sleep?

Swordtails need at least 12 hours of sunlight daily to be active. The fish will lose their color, stop feeding, become unwell, or become lethargic if not exposed to light. On the other hand, the aquarium lights will wake up your swordtails if left on all night.

Lack of sleep leads to increased tension, which can lead to the fish’s death. Allow plenty of time for the swordtails to slumber. At night, remember to switch off the lights or set a timer.


In summary, sleep is essential to the swordtail fish, so that lack of it can cause problems for the fish.

Sleep solidifies and consolidates information in addition to repairing and healing the body. Therefore, it is essential to ensure that the lighting is controlled so that the sleeping habit of the fish are not altered.

The swordtail fish should have lighting for at least 12 hours daily to remain active. It’s essential to give the fish enough time to sleep by ensuring that they are not in darkness all the time and at the same time, the light is also restricted.

Leave a Reply
Related Posts