How Do Fish Sleep In A Tank? | What Does A Sleeping Fish Look Like?

Last updated on December 24th, 2022 at 11:05 am

How Do Fish Sleep In A Tank? Observing underwater life, aquarists wonder if the fish are sleeping in the aquarium. It seems that the fish are always awake in the aquarium, do not hibernate. The way fish sleep has its own characteristics, and you need to consider the daytime and twilight activity of pets, settling them together.

How Do Fish Sleep In A Tank

The dream of a fish is different from that of a human: the fish does not turn off completely, but slumbers, wakes up at the slightest danger. Therefore, you need to know how fish sleep in an aquarium in order to create comfortable conditions for pets.

Do Fish Sleep?

Looking at floating pets, aquarists doubt whether the fish are sleeping in the aquarium because it seems that they are always cheerful and active. In fact, all the inhabitants of the planet with a developed nervous system need rest, and fish are no exception.

All types of fish have a sleep and wakefulness regime. However, the dream of a fish is different from that of a human. Living in an open aquatic environment has left an imprint on the evolution of fish sleep. Since, in nature, fish are forced to continually be on the lookout to notice a predator in time or grab food, they do not turn off entirely but only doze.

When the fish is asleep, its brain does not go into the deep sleep phase but continues to work. And for the brain cells to rest and recover, the hemispheres work alternately.

Whether fish sleep in an aquarium at night or stay awake in the dark depends on the species. Some species are active during the day, and others prefer to stay awake at night. So, aquarium catfish are active at night, and in the daytime, they can be found in a shaded shelter.

Dolphins are known to be aquatic mammals. However, their brains, like those of fish, can turn off the hemispheres alternately. First, one hemisphere rests for about six hours, then the other for the same amount of time. Therefore, dolphins are always on the lookout, spotting predators in time

Do Fish Sleep

Since sleeping fish are stressed when they are disturbed, the optimal conditions for the rest of the pets must be created in the aquarium:

  • Build shaded shelters
  • Place species with the same sleep patterns in the same aquarium
  • Do not turn on the aquarium light when pets are sleeping.

What Does A Sleeping Fish Look Like In a Tank?

Many aquarists have no idea how aquarium fish sleep. They believe that a sleeping pet should have their eyes closed. In reality, the fish has no eyelids. She does not need them because the functions of the eyelids are to preserve moisture and protect the eyes, and in an aquatic environment, water does an excellent job with these functions. Therefore, a fish that wants to rest hides in a shaded place.

You can only understand that a fish is asleep by its behavior. How an aquarium inhabitant sleeps depends on its species. Each species has its own way of sleeping.

How Do Fish Sleep In An Aquarium

How Do Fish Sleep In An Aquarium?

  • Hanging motionless in the water column
  • Lying on the bottom sideways
  • Swimming with the current near the surface of the water
  • Catching on to underwater vegetation
  • Buried in the ground with a belly.

There are also exotic options for how fish sleep. So, a parrotfish, getting ready for bed, produces a slimy mass with special glands, which envelops itself like a cocoon.

Cartilaginous species are the most difficult to sleep. Bony fish have a swim bladder, due to which the sleeping individual hangs in the water column. And cartilaginous fish do not have an air bubble, so they have to sink to the bottom, lie on their side or bury themselves in the ground. For example, catfish do this.

And most of all, cartilaginous fish are not lucky sharks. They do not have not only a swim bladder, without which, in the absence of movement, they instantly sink to the bottom, but also gills. Sharks only have gill holes, which do not get water if the fish is in a static position. Therefore, the shark has to constantly move in order not to suffocate.

Related: Feeding Aquarium Fish | Don’t Overfeed Your Aquarium Fish

How Sharks Sleep With These Anatomical Features:

  1. There are species that are guided by the bottom current, open their mouths in the direction of the movement of the water mass so that it flows around the gill openings.
  2. Some sharks have sprites – rudimentary canals behind the eyes that allow water to pass through the mouth opening.
  3. Many shark species generally sleep when moving. The brain is disabled, but the spinal cord continues to work, controlling the movement of the fins.

But no matter how the aquatic inhabitants sleep, they instantly wake up when they suspect a danger. How long the fish sleep depends on its condition and environmental conditions, but the minimum duration is 5 minutes.

What Does A Sleeping Fish Look Like In a Tank

Classification Of Fish By Activity At Different Times Of The Day

By Activity At Different Hours, Fish Are Divided Into:

  1. Dusky are mostly carnivorous species. They see perfectly in the dark, hunt at night, and rest in the daytime.
  2. Daytime – these are species that rest at night, leading an active lifestyle during the day. For example, guppies, scalars, cockerels.

An aquarium with fish should be organized so that daytime crepuscular species do not live together. Otherwise, nocturnal predators will begin to hunt for neighbors, and in the daytime, they will suffer from an excess of light.

Winter And Summer Hibernation

So that hibernating pets do not cause surprise, it is important for aquarists to know if aquarium fish are sleeping at the onset of an unfavorable season. Not all species do this. And such a state cannot be called a full-fledged sleep. It is rather a decrease in metabolic processes.

What To Do To Keep Your Fish Under Stress

How To Understand That The Fish Is Hibernating:

  • She becomes inactive
  • Does not perform the usual actions
  • Hides in a shelter or sinks to the bottom of the tank.

Fish freeze in natural conditions, not only in winter but also in the summer dry period. So they are saved from deadly dehydration. However, at home, aquatic inhabitants rarely remember the natural cyclical nature of their behavior and remain active all year round. How often domestic fish can go into a daze depends on the conditions: if it is in discomfort, it can fall asleep regularly and for a long time.

The Importance Of Knowing About Fish Sleep Patterns

The main reason why it is important to know how fish sleep in an aquarium is to create the right conditions for them.

What To Do To Keep Your Fish Under Stress:

  • Turn off the lights at night
  • Buy representatives of species that have the same regime
  • Shade the aquarium with aquatic vegetation if it is home to crepuscular species.

Many aquarists are interested in seeing sleeping fish. To catch them at the time of rest, you need to sharply turn on the lighting in the dark. For a couple of seconds, you will be able to see how the pets are sleeping. Then they, frightened by the light, wake up and become active again. 

1 thought on “How Do Fish Sleep In A Tank? | What Does A Sleeping Fish Look Like?”

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