Is my Guppy Sleeping or Dying?

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Due to various reasons — sleeping, illness, pregnancy — the activity levels of guppy fish may change causing inexperienced aquarists to wonder whether their guppy fish are sleeping or dying.

Being active and alert is a typical behavior trait of guppy fish, so it’s completely understandable that you’d worry if your guppy doesn’t seem to be as active anymore.

To help you decide if your guppy fish is sick, dying or just simply sleeping, I’m going to discuss how to identify sick guppy fish, how guppies behave when their sleeping, and what to do if your guppy is dying or already dead.

Guppy Fish Sleeping Behavior

You may be surprised to find out that guppy fish do indeed rest at night. Because they’re diurnal fish, their sleeping pattern is like that of humans in the sense that they’re active and awake during the day, and rest during the night.

This is the reason why aquarists recommend shutting off your aquarium lights at night and follow natural day-night patterns to allow guppy fish to rest during the night.

It’s unclear why guppies require sleep and how much of it is actually needed for them, but it’s theoreticized that they require rest to conserve energy and recover.

So, how can you tell if your guppy is sleeping? Normally, if guppy fish are healthy and happy, you won’t see them hiding in the aquarium or being motionless, unless it’s nighttime.

If your guppy fish is active during the day and shows no other signs of illness (lethargy, loss of appetite, bloating, injuries, infection, etc.), but it’s motionless or hides during the night, there’s nothing to worry about, your guppy is just exhibiting normal sleeping behavior.

As the night sets in and you turn off your aquarium lights, you’ll notice that your guppy becomes motionless, it may float above the gravel, or next to the plants in your tank.

Their breathing may slow down and they may seem a bit discolored (don’t worry, colors will come back as soon as you switch on the lights again).

Guppies don’t move around while resting, although you may notice slight twitches or so, but nothing too obvious.

If you notice all these during the night and your fish behaves normally and it’s active during the day, then everything is as it should be.

The same cannot be said if the same behavior happens during broad daylight. When guppy fish lay motionless at the bottom of the tank, there’s usually something else going on.

Identifying Sick Guppy Fish

As I mentioned, a guppy fish that floats in the aquarium or that’s motionless during the day is most probably not sleeping. In fact, chances are high that she’s either sick or pregnant.

If your female guppy is hiding at the bottom of the tank, it’s possible that she’s pregnant and preparing to give birth.

Besides this hiding behavior, a female guppy fish will also have an extended belly, a darkened and enlarged gravid spot.

But what if it’s a male guppy that’s hiding at the bottom of the tank in daylight? Although some sort of illness or disease is the most likely explanation, it could be that your male fish was bullied or even injured by other fish, so it’s hiding at the bottom of the tank.

Either way, you should look for signs of disease. Here are some signs of guppy fish diseases that can help you determine if your guppy is sick or not:

  • Bloated, enlarged abdomen (it can be caused by constipation) or scales sticking out (a sign of dropsy disease);
  • White spots on the body of your fish (most commonly a symptom of ich or ick disease);
  • Rotting tails or fins (fin rot disease);
  • White splashes on the body (Columnaris and mouth fungus disease);
  • Swollen gills (ammonia poisoning);
  • Red blood spots on belly (ammonia and nitrites poisoning);
  • Lesions, ulcers, sores on the belly (viral haemorrhagic septicaemia);
  • Protruding eyes (sign of an infection, dropsy, parasites, etc.);
  • Fish swimming upside down (swim bladder disorder);
  • Hole in head or body (hexamitiasis);
  • Bent spine (scoliosis);
  • Hollow belly, ulcers on body, fin rot, discoloration (fish TB).

As you can see, there are many diseases affecting guppies, therefore, I encourage you to familiarize yourself with the most common guppy diseases and remedies to know what to do in case your guppies get sick.

What to Do with Dying Guppy Fish?

Depending on the disease affecting your guppy, you can try the recommended treatment for the specific illness your guppy has, or, if it’s an incurable disease, you must consider euthanasia.

Either way, if you notice a sick fish in your aquarium, remove it immediately and place it in a hospital tank for further diagnosis and treatment.

It’s important to act fast and quarantine sick or dying fish to avoid the spread of the disease to other fish in your aquarium. Depending on the type of the disease, you’ll need to apply treatment not only in the hospital tank but also in the home aquarium.

Fish euthanasia can be a heart wrenching moment, but it’s better than leaving your fish to needlessly suffer.

There are various methods to euthanize fish, but only two of these involve minimal suffering — the clove oil method and the stun and stab method. Both are recognized as humane ways to end the suffering of your fish.

The clove oil method requires you to first add a clove oil mixture in recipient that can hold a gallon or so of water, which will act as an anesthetic, then by increasing the dose you can induce hypoxia and put down your fish.

The stun and stab method is a bit more gruesome and not for the faint of heart, but it’s still a fast and efficient way to humanely put down your fish.

It involves hitting the head of the fish with a blunt object, then stabbing the brain of the fish, which will kill it instantly.

If your guppy is suffering from an incurable disease or the disease has progressed too far and it’s no longer reversible and your fish is suffering, euthanasia is the most humane way to deal with a dying fish.

Do Guppy Fish Sleep Upside-Down?

I mentioned that if you notice a guppy fish swimming upside down, the issue is probably a swim bladder disorder or infection.

If your guppy fish appears to be sleeping upside-down, it’s probably already dead or very close to dying.

You can try to diagnose the problem (is it bad water conditions or a swim bladder malfunction?) and perform a major water change or administer medication to see if it helps.

Unfortunately, if your fish is motionless and floating upside-down in the aquarium, it’s probably already dead in which case you should immediately remove it from the aquarium and dispose of it.

How to Dispose of Dead Guppy Fish?

There are multiple ways you can dispose of a dead guppy fish; however, some methods are better than others. Also, there are definitely methods you shouldn’t use to dispose of a dead fish.

Flushing your fish down the toilet — dead or alive — is a bad way to dispose of it. If it’s still alive, you should euthanize it first, as the sudden change of water parameters (aquarium water to toilet water) will only prolong its suffering.

Once you’re sure your fish is dead, you should still not flush it down the toilet. If it’s sick, it will decompose it will continue spreading diseases in the water system, so it’s best if you cremate it.

You should also avoid feeding it to other fish as it can transfer diseases and make your other fish sick.

You should consider cremation (if it’s allowed in your area), because cremation will ensure that your fish isn’t decomposing and potentially spreading disease.

Alternatively, you could bury your fish, but do make sure you bury it deep in the ground so that no animals can dig it up and consume it.

Some aquarists recommend placing your fish in a Ziplock bag and throw it out in the trash. This too can be an option when disposing of dead fish.

Therefore, when disposing of dead fish, you should think about the safety of other ecosystems and animals. You should never flush your fish down the toilet, leave your fish out for stray animals or your pets to eat them, and you should never throw your fish in a pond, river, or lake.


To sum up everything: guppy fish resting at night is not a cause for alarm, but guppy fish exhibiting the same behavior during the day is not normal and you should investigate its health status.

Now that you know how to identify a sick guppy fish and tell the difference between a dying guppy fish and a sleeping one, I’m confident you’ll be able to take better care of your guppies.

I hope my article can serve as a good basis for you to do further research on the diseases that can affect guppy fish and the behavioral changes that are normal (e.g. hiding while preparing to give birth) and those that are not.

Updated: February 8, 2022
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