Do Fish Sleep on The Bottom of The Tank or Are They Sick

Fish in your Aquarium are hard to figure out sometimes. If the tank is not right, the fish could be stressed, sick or worse, and can be found on the bottom of the tank.  Do Fish sleep on the bottom of the tank or are they sick?

Yes, Most fish sleep just off the bottom of the tank, floating and moving slightly in an upright position, 9-12 hrs. per day. Sometimes a pair or group close to the structures or plants in the tank provide some security from unknown dangers. 

There has to be some sleep time, for fish in your aquarium and since they don’t close their eyes and lay down it’s a little difficult to know when they do it. They also hang on the bottom when their stressed and sick, it’s good to know the difference between when a fish is having a good night’s sleep or is stressed and diseased. Here are some ways you can tell.


How Long Do Fish Sleep


Just like humans fish require time to sleep. The best time and the most natural time for them to sleep is when the lights are out in the aquarium. They will tend to hover in one place in a trance like-way that appears differently than they normally do. As the owner of the aquarium, you need to mimic a natural existence by turning off the light at the same time every night.

Do Betta Fish Sleep? How, When & Why They Rest (Explained)This will provide them a night and day scheduled clock, almost what they would experience in a natural environment where they can wind down and then fall asleep.

Most Fish need to move to breathe, so even though they are sleeping, they will move slowly pulling water through their gills to provide oxygen to their bodies.

Others have an adaptation called spiracles that force water past the gills and allow the fish to stop swimming for a good night’s sleep. Fish will sleep between 9-12 hours a night normally near or at the bottom of the tank.

Some will move their tail to keep oxygen moving through their gills but it’s pretty easy to tell the difference between a fish that is stressed and a fish that is tired and trying to snooze if you examine them and know their routine.

A fish sleeping in your aquarium will remain upright on the bottom of your tank at the same time or near the same time at night. It will find a safe place in between rocks, plants, or some kind of structure until he wakes and is refreshed. Some fish may burrow themselves in sand or pebbles at the bottom of the tank.

Some fish, like the Parrotfish, will excrete mucus to surround themselves as they rest. In most stages of rest, a fish will wake up at the slightest sound or if the aquarium lights go on. It’s just a matter of survival.

In the real world of fish, a shark can sleep so sound, at night in the ocean, that oceanographers can actually lift the shark up and out of the water without waking it. The shark isn’t worried about any fish gobbling him up.

Some fish will float an inch or so off the bottom others or will lay on the gravel at the bottom with other fish who keep them off the menu of a predator fish. They will sleep together paired off with a buddy in between objects in the aquarium that can act as cover for them.

Most people who own aquariums believe that fish like other pets will sleep when you sleep and get up when you get up. That turning the light off settles them down and helps them go night-night.

So even though they are not closing their eyelids and laying down flat, they’ll have a period when activity and metabolism slow way down as a way to conserve energy and restore the energy levels in their body just like any creature on earth.


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Is It Normal for a Fish to Lie on The Bottom of The Tank


So for most fish to get some rest, it’s important for fish to find a place at the bottom of the aquarium to nettle in and get some quality time. It’s quite normal for you to see your fish nettled between some plant and hunkered in for the night. The problem is when to recognize that it’s not normal and the fish is acting strangely, especially at the bottom of the aquarium.

You need to know the difference between a fish that is sleeping and a fish that is stressed. Pay attention to your fish and they will show you what they need to know. Do your water testing, know what the parameters are, and what important role they play in the role of the aquariums’ ecosystem. You can find anything for your Aquarium system right here on  

This site can give you the information you need for a successful aquarium along with testing equipment like digital meters that can keep you a step ahead of your Aquarium. If you are busy and need an easy way to monitor try an Electronic tester like this that is reliable and easy to use Bluelab MONGUA Guardian Monitor for pH, Temperature, and Conductivity Measures, Easy Calibration and Wall Mounted 


A  fish that is Stressed at The Bottom of the Tank                          

  • Is the fish laying on his side? Fish will keep themselves upright, balanced, and in place slowly moving their fins. These motions will not be giving them any focused directional movement. You will probably notice that your fish has a droopy tail, as well.
  • Decreased activity of the mouth: Fish won’t move their mouth while they are sleeping.
  • How long has the fish been laying on the bottom? Normally fish will sleep 9 to 12 hours and will wake up with aquarium light or noise. Drop a flake of food next to the fish and the fish won’t respond.
  • If you have a fish in your freshwater aquarium that appears to be sleeping on his side or on his back, a serious ailment known as swim bladder disease is the culprit.
  • if the fish is laying on the bottom of the tank and his gills have a reddish or purplish look or the fins appear to be streaked with red — your tank may have a high ammonia content. Or an Oxegen content where the fish is looking for more at the bottom.
  • Check parameters for the aquarium, PH, Nitrates, ammonia, Oxygen, and temperatures.


A fish that is Sleeping on the Bottom of the Tank 

  • A fish that is sleeping will have a subtle loss of color that will return to normal after it awakens.
  • Fish will likely doze off at the same time every day. That time could be brought on when the lights are turned back off giving him the sense of day and night.
  • Fish do show some signs of being asleep like being unaware of their surroundings, bumping into things in the tank, slowed fin and tail movements, less frequent body movements, and becoming inactive around the same time every day or night.
  •  If the fish is sleeping will show no signs of sickness or death which could be sunken eyes or a bloated body.
  • A fish that is sleeping at the bottom of the tank will have no movement in their mouth.
  • The fish could be exhausted if you are leaving lights on and the fish can’t sleep and show signs of exhaustion. They aren’t sick but will get sick. Shut out the lights and see if it makes a difference.
  • Try and net the fish, a sleeping fish will awaken and struggle no matter how sound asleep he is.
  • Check for movement-if it’s moving it’s breathing.


Proper pH For Freshwater Aquarium


A sick fish can look like he is sleeping. If you have determined your fish is still alive but very sick, research his symptoms to see if medicating with drops first, might help him or a water change may help. If you choose to end his suffering, you can euthanize him with clove oil.

Separate the fish into a breeding/separate tank and add about 400mg of clove oil to one liter of water. The clove oil will cause the fish to lose oxygen, and he will pass away peacefully. This method is far more acceptable than flushing your finned friend fish in the toilet bowl.


Check all your equipment like thermometers and heaters and all your parameters test Ammonia, Nitrates Oxygen, and pH. Check all inhabitants of the Tank and make sure they coexist together, Include the fish and the plants too. Make sure you are not overfeeding the fish which can lead to Swim Bladder Disease when a fish eats too much and gulps air or is in water that’s too cold.

A sick fish may have spots. Check for color changes, patches, or a slime coat. Most conditions can be cured with an additive or some specific medications.

Balance dark and light, In the same way, they would experience in the wild. Some fish are nocturnal, meaning they are active at night, while others are diurnal, meaning more active during the day. Both types of fish will require a good balance of light and dark to sleep and function as naturally as they can.

Make sure the fish isn’t experiencing an external source of stress or an internal source of stress. You can experiment with a few different explanations of what may be or may not be happening but with the exception of a few fish.

Most fish sleep on the bottom of an aquarium with a buddy or two, where the structures provide some security from any unknown dangers. Know what Aquarium’s water chemistry is and how to change things when they’re not.


Remember to shut out the lights every night to give your fish a sense of day and night. Sometimes the best medicine is just a good night’s sleep. Never touch a fish’s gills, they are extremely delicate, and just touching them can damage them. Never lift a fish out of the water by holding the belly area.


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JimGalloway Author/Editor





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