Is My Fish Dead Or Sleeping? (All You Need To know)

When we walk by our home aquarium and suddenly detect that one of our fish is not moving or floating at the top of the tank, it makes us worry.

In such a situation, we need to confirm if our fish is okay, sick, or dead.

So, Is my fish dead or sleeping? Let us find out.

Moving your fish using a fish net is the best way to detect if your fish is dead or sleeping. If your fish suddenly try to get free from the net, they are sleeping; if they don’t show any movement, they are dead. Also, look for the movement of gills to detect whether they are resting.

This article will discuss how to know if fish is sleeping or dead. Also, we will discuss how to treat dying fish and what to do with a dead fish. So, let us get into it.

How to tell if fish is dead or having rest?

Fishes have sleeping behavior that will easily indicate to you that they are having a rest.

A dead fish will develop a pale body. There will be complete no movement for a long time ( Like hours).

If your fish is sick and you suddenly see that they are not moving or floating at the top of the tank, they are probably dead.

If you see your fish upside down, floating, or sinking at the bottom of the tank, they are probably dead.

The best way to find that your fish is sleeping or dead is by moving them.

Try to scoop your fish into the fishnet, if they are sleeping, they will suddenly be active and try to wriggle out of the net, and if the fish is doing no movement, then they are dead or in critical condition.

Another best way to find out if your fish is sleeping or dead is by looking for breathing.

Fish require oxygen which they get when the water passes through their gills. So, there will be some movement in their gills. When you look closely, it will be noticeable.

If they are breathing, it means they are resting; if not, something is wrong.

Fish sleeping behavior.

Most researchers prefer to call it rest rather than sleep. 

This is because fishes don’t sleep like us humans. 

Most of the fish don’t have eyelids, and they have to rest with their eyes open.

All these behavior indicates that your fish is resting or sleeping:

  1. Your fish has not moved for a few minutes.
  2. When you drop the food in the tank or turn the lights on, your fish takes more time to respond.
  3. Fish float in one spot or stay at the top, bottom, or beneath the substrate for a few minutes.
  4. They rest at the same time every day.

Fishes can be diurnal, which means they will stay active in the daytime and rest at night, and nocturnal, which means staying active at night and resting during the day.

Some fishes like corydoras will take rest whenever needed. So, you will see them having no movement for a few minutes and then getting back to work by digging into the substrate in search of food.

Fishes require oxygen which they get when the water passes through their gills. So, while they are at rest, you will notice some movement in their body. 

Also read: Do Goldfish Sleep?

How to detect if my fish is sick and dying?

All these behavioral changes will tell you that your fish is sick and dying:

  1. Weakness
  2. Loss of appetite
  3. Flashing
  4. Remaining at the top of the tank
  5. Staying at the bottom of the tank
  6. Fish not being able to maintain their buoyancy.
  7. Fish having clamped fins.
  8. Erratic swimming


A sick fish will become weak and will not be able to do much movement in the tank.

The loss of appetite due to sickness will make them weak and prone to other issues.

You will find them sitting at one spot in the tank and not swimming as they do regularly.

Loss of appetite

A sick fish will lose their appetite and will not be much interested in eating.

Whenever you provide food to them, they will eat only a few or will altogether avoid eating.

All these will make them weak and lose their immune system, becoming prone to various diseases and parasites.


Flashing is the behavior that fish uses to itch their body.

Many infections (Mainly parasitic infections) cause itchiness in our fish bodies.

Though they don’t have hands, so they use other objects inside the tank to scratch themselves for some relief.

Not treating such issues in the early stage can result in your fish passing away.

Also read: Why Is My Goldfish Rubbing Against Plants?

Remaining at the top of the tank

The lack of dissolved oxygen in the tank makes your fish stay at the top of the tank.

The surface of the tank has the highest oxygen level, and when the tank water lacks oxygen, fish swim upwards to the surface for gasping air from their mouth.

Inadequate water parameters can result in oxygen deficiency in the tank. 

Another reason like an overcrowded tank can also lack oxygen in the tank.

It will affect your fish by making them come under stress, and also they can pass away.

Also read: Why Is My Goldfish Swimming At The Top Of The Tank?

Staying at the bottom of the tank

If your fish is active and not a bottom dweller but spends most of its time at the bottom of the tank, it is sick and going through some issues.

A weak fish will become lethargic and not be interested in moving from one place to another.

Poor water conditions and a stressful environment make your fish weak and lethargic. 

Also read: Why Is My Guppy Sitting At The Bottom Of The Tank?

Fish not being able to maintain their buoyancy.

Swimbladder disorder is the reason your fish cannot maintain their buoyancy.

Sinking to the bottom of the tank, floating at the top, having a distended belly, turning upside down, and struggling to stay upright are the symptoms of swimbladder disorder in fish.

Overeating, overfeeding, gulping air, and constipation can cause swim bladder disorder in fish.

Fish having clamped fins.

Clamped fins mean fish have fins nearest to their body and do not flow them as they should.

Inadequate water temperature and poor water conditions can cause such issues.

Such behavior shows that your fish is not in a healthy state and suffering from some problem.

They may be under high-stress levels, and too much stress will make them lose their appetite and become weak.

Also read: How To Treat Fin Rot In Cory Catfish?

Erratic swimming

Whenever the fish shows an erratic swimming pattern, there is something wrong.

Stress, disease, and injury can make your fish swim erratically.

All these situations can make your fish suffer from a critical condition, and they can even pass away.

Also read: Why Is My Cory Catfish Swimming Crazy?

How to treat my dying fish?

If your fish is sick and dying, you should first separate them and place them in a hospital tank.

Separating them is necessary for the safety of the remaining fish in the tank, as the disease can spread, and all of your fish can get sick.

Now, if there is a treatment for the disease, we recommend consulting your fish vet for proper medication and treatment.

Make sure to run the treatment in both tanks, including the hospital and home tank.

Running the treatment in the home tank is also necessary because it will ensure that your remaining fishes are safe and healthy.

These are some basic things that help your fish to recover fast and prevent them from various diseases and parasites:

  1. Adequate water parameters and stable water temperature
  2. Good water conditions
  3. A regular supply of food
  4. Feeding high-quality nutritional food
  5. Keep a regular check on Ammonia, Nitrite, and Nitrate levels of the tank and ensure that all are adequate.
  6. Stress-free environment (Avoid adding aggressive fish, provide hiding spots, keep in a large enough tank, and feed regularly)

Perform a weekly water change of at least 35% to keep the water clean.

Make sure to treat the water using a water conditioner to dechlorinate it.

We recommend using the API water conditioner to treat the water, as it will help you eliminate chlorine, chloramine, ammonia, nitrite, and heavy metals from the water.

You can buy this product on amazon: API TAP WATER CONDITIONER.

Provide your fish with a stable water temperature.

Consider adding a heater to your fish tank to ensure stable water temperature.

We recommend using the Fluval M200 Submersible heater for your tank.

You can buy this product at amazon: Fluval M200 Submersible Heater.

Keep a regular check on ammonia, nitrite, and nitrate, and make sure to maintain ammonia and nitrite at 0 ppm, whereas nitrate should be below 20 ppm.

We recommend using the API freshwater master test kit to check the ammonia, nitrite, nitrate, and pH level of your fish tank, as it shows an accurate result.

You can buy it from amazon:  API FRESHWATER MASTER TEST KIT.

Also, use a good filtration system with biofilter media to keep the water clean from excessive waste and protect your fish tank from harmful toxins like ammonia and nitrite.

You can consider using a Fluval high-performance aquarium filter for your tank, as it will ensure that your water is clean and protected from harmful toxins like ammonia and nitrite.

You can buy this product at amazon: Fluval High-Performance Aquarium Filter.

Now, if the disease or any issues your sick fish is going through is irreversible, and there is no treatment for such a condition, then you have only one option: euthanizing.

Euthanizing is not easy for the fish owners, but it is necessary to give your fish relief as they will be in pain every day until they pass away.

Also read: Is My Guppy Sleeping Or Dying?

What to do with a dead fish?

You have to dispose of your dead fish in the right way. 

There are many ways to dispose of a dead fish, but these two are the best way:

  1. Cremation
  2. Buring deep in the ground.

Cremation is a good choice for disposing of your dead fish as it ensures that the body is not decomposing and not spreading any disease.

However, if cremation is not allowed in your area, the next best option for you to dispose of your dead fish is by burying them deep in the ground.

While burying your fish, make sure to bury them deep in the ground so that any street animals can’t dig it up and eat dead fish.

You can choose these options when your fish has already passed away.

If your fish is sick and there is nothing you can do to reverse the situation, euthanizing is the option you will be left with, as your fish will suffer a lot of pain, and euthanizing will give them relief from that pain.

You can either choose the clove oil method or the stun and stab method.

Once you are sure that your fish is dead, you have to dispose of them. 

All these are the options you should always avoid when euthanizing the fish:

  1. Flushing them down.
  2. Letting them suffocate outside the tank
  3. Putting them in boiling water
  4. Releasing carbon dioxide in the tank
  5. Alcohol bath

Also read: How To Humanely Euthanize Guppy Fish?


The easiest way to find out if your fish is sleeping or dead is by moving them.

Use a fishnet to scoop the fish inside the net. If your fish is sleeping, it will suddenly wake up and try to escape the fishnet.

And if your fish don’t move, it means that it is either dead or suffering from a critical condition.

If you don’t want to disturb your fish and find out if it is sleeping or dead, then look for the movement of gills.

Fishes need oxygen which they get when the water passes through their gills, so when you look closely, you will detect some movement in the gills.

If there is no movement in the gills, there is something wrong.

Reference: Oceanservice, SleepFoundation,

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