Do Cory Catfish Sleep?

Cory catfish gradually drift into short rest periods by reducing activity and lowering metabolism functions. They can rest in odd positions, such as leaning against rocks or vegetation. Some have been found to bury themselves in soft sandy substrates with only their tails sticking out.

Most land animals use sleep to rejuvenate, allowing the brain to shut down, process information from the day, and give the body a chance to recharge. It poses the question of whether fish possess the same need, and since they have no eyelids, can they sleep?

Do Cory Catfish Sleep?

There is still much active research being done on the sleep patterns of cory catfish. Still, like most land animals, fish need to get sleep, which may provide the fish a similar restorative function that rest offers humans.

When we say cory catfish sleep, it’s not meant in the same essence as how humans, dogs, cats, or land animals sleep.

Cory catfish don’t tuck in for the night and get a good eight hours of rest. Instead, they go into rest periods of five to ten minutes at a time, with some having been noted to prolong the nap by up to twenty minutes. These little naps can be considered the equivalent of a human power nap.

Cory catfish in natural environments need to remain alert for dangers and be able to react quickly to changes around them if need be. However, in aquariums, cory catfish can be slightly more relaxed as they do not have to be afraid of predators. That means having community fish that go together, so avoid larger fish that could prey on your cory catfish.

Cory Catfish Close Up

How To Tell When Your Cory Catfish Are Sleeping?

Finding your cory catfish lying on its side or motionless at the bottom of the tanks can cause alarm for any aquarium keepers.

As you grow accustomed to your fish, their characteristics, and personalities, yes, fish also have personalities, and you start to understand their particular mannerisms.

Some of the positions cory catfish will take when sleeping include:

  • Lay motionless on the aquarium substrate
  • Hang in suspended animation above the aquarium floor
  • Lean against decoration, rocks, or vegetation
  • Choose to lay on their sides at the bottom of the tank
  • Bury their heads into sandy substrates
  • Wedge themselves under driftwood or decorative caves
  • Some even look like they are standing upright

How Do Cory Catfish Sleep

Cory catfish do not have eyelids to close their eyes and induce sleep.

So how do they sleep with their eyes open?

Like most tropical fish, it seems that cory catfish enter a reduced state of consciousness. They are not quite asleep but not entirely unconscious.

They slow down their movement, reducing the fin and gill actions with the occasional twitching of a fin to balance themselves. Their breathing and metabolism rate reduces while their heart rate drops and their brain functions slow down.

Because fish don’t depend solely on eyesight to warn them about impending dangers, the connection between the brain and eyes is disconnected, reducing responsiveness to external stimuli.

Cory Catfish will rely more on sound, smell, and lateral lines to warn them of dangers and quickly rouse them from their naps.

D.W. [Public Domain]

When Do Cory Catfish Sleep

Cory catfish are diurnal, meaning they are more active during the daytime. Most of the day is spent playing, socializing, mating, and feeding. However, they will rest for short periods during the day to replenish energy.

During the nighttime, they will be far less active, huddling in groups at the bottom of the tank and indulging in more extended periods of naps.

Research has shown that, like other animals’ fish have hormones that signal sleep cycles that can be affected by light sensitivity.

Some studies show that freshwater fish will, in total, spend about ten to twelve hours resting and entering periods of inactivity spread out over the course of twenty-four hours.

What Can Affect The Sleep Pattern Of Cory Catfish?

There are various reasons why a cory catfish may not get the rest it needs.

Cory catfish are timid fish, some species more than others, and will often find a well-covered hiding place to get some rest. However, not providing enough hiding places with plants and cave-like decorations will keep them from resting appropriately.

Some cory catfish love burrowing themselves into soft sandy substrates, so ensure you have at least 2 inches of sand for your cory to tuck itself in.

Pairing suitable community tank mates with your cory catfish will ensure they feel comfortable enough to take a break. Don’t add large fish that could easily swallow your little cory. Keep tank mates in the same size category.

Avoid having nocturnal bottom feeders that could possibly eat your cory or any cory predator fish that could prevent them from feeling confident enough to rest.

What Are The Effects Of Lack Of Sleep?

Just like us, if your cory catfish don’t get enough rest, in whatever odd position it shows preference to, their health can start to suffer, putting the cory’s life in danger and possibly risking the aquarium tank to diseases and infections.

Not getting enough sleep or rest to restore the body’s system can lead to some signs that cory catfish don’t get enough rest:

  • Reduced immune system
  • Vulnerable to parasitic conditions
  • Susceptible to bacterial infections
  • Sluggishness and slow metabolism

Do Cory Catfish Yawn?

You may catch your cory catfish in what looks like a great big yawn, but they don’t yawn, or any fish for that matter.

What may look like a yawn is your cory catfish actually just clearing its gills with water.

In some cases, if you find your fish gaping more often than usual, it means that your water has low oxygen levels.


Cory catfish are known to catch a few Z’s to replenish their energy, but for cory’s, it’s more of a power nap than a deep slumber. Nevertheless, sleep is still an essential function that allows cory catfish to perform their daily activities and scavenge for food during the day with a few strategically placed power naps in between, while the cover of darkness provides them with more time to rest.