Is Guppy Fish Sleeping or Dying?

Guppies, like many other aquarium fish, are active and energetic creatures. They like to explore their environment, interact with other fish, and roam around the tank constantly.

Due to their small and simple bodies and limited behavior, guppies tend to act similarly in vastly different situations. They tend to display similar behaviors, whether they’re dying, sleeping, getting sick, experiencing labor, or showing stress. For this reason, seeing them immobile or swimming slowly in place can concern most people.

It’s up to you to distinguish between all these potential causes, which could make the difference between life and death for your guppy.

Today, we will discuss guppy behavior and how to interpret the various signals that your guppy is sending.

There are several reasons why your guppy may be rendered immobile or display slow-to-no movement:

Guppy Sleeping Schedule

Guppies, like all fish, have a pretty well-defined sleeping schedule. They abide by the day-night cycle just as we do, which means they will rest and sleep during nighttime.

It’s unclear how much guppies sleep, but it’s undeniable that they rest when lights go out. This is why you should provide your guppy with a regular light-dark cycle, preferably matching the sun’s movements.

If it’s day outside, keep the tank’s lights on. Only turn them off when the night arrives. This cycle will allow the guppies’ nervous system to reset and refresh so that the guppies can wake up in the morning all energetic and happy.

It’s not difficult to tell whether your guppies are sleeping or there’s something else at play. The most relevant indicator is the time when the guppy displays sleeping behavior. If it’s only during nighttime and you see the guppy only performing subtle twerking movements but otherwise staying motionless, that’s sleeping.

The guppy will only move slightly to keep its body in place – most likely an instinctive reaction of the autonomous nervous system, just like breathing.

If your guppy returns back to normal when morning comes, there’s nothing to worry about. You are witnessing normal sleeping behavior.

Stress In Guppies

Unfortunately, there are many things that can stress your guppies. This includes water quality, low oxygenation, constipation, bullying from other fish, parasitic infections, etc. When that happens, the guppy will generally look to hide behind plants or rocks or swim near the substrate, attempting to find cover. It may also lay motionless at times and only use jerky motions to float in place.

The key here is to identify the cause to prevent the situation from aggravating rapidly. A stressed fish won’t eat, will become inactive, and will have a lower immune system, making it prone to parasites and infections.

Have water monitoring devices in place, verifying oxygenation, temperature, and ammonia levels. You should correct any disruption you find fast so that the parameters show acceptable values.

You should also not pair guppies with larger, aggressive, and territorial fish. These can attack, bully, and even kill guppies.

Guppy Sickness

Guppies can suffer from a variety of health conditions that will affect their behavior dramatically. The ‘good’ news is that erratic swimming patterns and lack of activity are but two of the many other symptoms available.

If your fish is sick, you shouldn’t have too many problems figuring out the cause. Here are the most common fish illnesses that could affect your guppies’ swimming behavior:

  • Fish Tuberculosis – The guppy will display a hollow belly, fin rot, and paler colors.
  • Scoliosis – Scoliosis comes with the bent spine syndrome, affecting the guppy’s swimming ability and buoyancy
  • Constipation – Refusal to eat, drastically bloated abdomen, and periods of inactivity.
  • Dropsy Disease – Pale gills, body ulcers, curved spine, swollen belly, and a swollen and red anus. This condition is deadly and contagious, and immediate quarantine is necessary to prevent other fish from contracting it.
  • Ich Fish Disease – The main symptoms include white spots on the body, abnormal hiding behavior, and loss of appetite. The ich disease is the most common condition for aquarium fish.
  • Fin Rot Disease – The guppy’s fins will turn brown or black, show an inflamed base, and begin to rot and fall away.
  • Ammonia Poisoning – The fish will initially swim near the surface, seemingly gasping for air. It will then display red spots on its belly and fins, and, eventually, the guppy will clamp its fins and lay on the substrate.

All these conditions will influence your guppy’s behavior, including appetite and swimming pattern. In most situations, the guppy will try to hide or sink near the substrate, attempting to escape the discomfort.

Many of these conditions are deadly, so I advise that, whenever you see your fish acting weird, investigate the cause. It’s not so much for the sick guppy’s well-being but for the well-being of the rest of the healthy population. You will probably need to euthanize the ill guppy anyway, but at least you will save the rest of them.

Pregnancy in Guppies

Pregnant females will also display hiding behavior, especially during labor. They will do so instinctively, looking for a spot where the fry will be safe once born. The female guppy will present an inflated abdomen, which doesn’t say much since this can also be a symptom of illness.

This means you will have to look for additional signs like the pregnancy spot. This is a dark spot in the lower abdomen, near the base of the tail. It will become progressively darker as the pregnancy evolves, reaching a prominent black shortly.

The gestation period varies between 21 and 30 days, but it can go beyond these parameters, depending on environmental conditions, water temperature, etc.

If your guppy is pregnant, I suggest removing it from the tank before delivery. This will allow you to protect the fry and grow them separately for the first several weeks of their lives. This approach will allow the fry to grow and strengthen themselves enough to survive in the main tank.

Be aware that guppies can give birth even if you’ve never had a guppy male in the tank. If you’ve bought the guppy females from a fish shop, chances are they have already mated. The female can store the male’s sperm up to 10 months and use it monthly to impregnate itself.

Many guppy owners don’t know about this guppy behavior, which leads them to disregard the possibility of pregnancy altogether. But now you know.

Your Guppy is Dying

If your guppy shows signs of advanced illness, its time may be running. As a result, its behavior will change dramatically, displaying a lack of appetite and looking for hiding spots.

If you identify any signs of disease in your guppy, you need to act fast. The illness may be contagious, in which case it will transmit to the other fish. Not to mention, fish TB also transmits to humans.

First, you need to identify the sickness responsible. Depending on the condition’s nature, you will quarantine the guppy and apply the necessary treatment, including in the main tank.

If the treatment fails, euthanasia will be your only other option.

If you care about your guppy, you should consider a human method of euthanasia. There are two available that I consider to be the most humane:

  1. The Clove Oil Method – You mix the oil with water into a separate recipient and place the fish inside. The clove oil will induce anesthesia, followed by hypoxia. It is a painless death, since the fish isn’t conscious to witness it.
  2. Stun and Stab – This is a more brutal method, not for the faint of heart. It goes in two stages, just like the name suggests – first, you stun the fish by hitting it in the head with a blunt object. Then you stab its brain again, leading to a painless and rapid death.

I advise looking for signs of fish illness whenever your guppy displays erratic swimming behavior. This will help you prevent conditions that may transmit to other guppies and infect the entire tank.

Do Guppies Sleep Bellies-Up?

No, they don’t. They also don’t swim belly-up. Their bodies aren’t designed for swimming or resting that way. If you see your guppy floating upside-down, investigate the matter since the guppy is either dying or already dead.

Removing the guppy from the tank is essential to prevent whatever killed it from spreading to other guppies as well. You can also treat the water with antibiotics, verify water parameters, and even perform a water change if necessary.

What to do With a Dead Guppy?

If you have a dead guppy on your hand, you need to dispose of it somehow. It shouldn’t be too difficult since we’re talking about a several-inch-long fish, not a horse.

However you consider disposing of it, just remember to be thorough about it. If your guppy has died of unnatural causes (disease), throwing it in your yard, flushing it down the toilet, or even feeding it to your aquarium fish are all bad ideas.

You don’t know how the dead guppy’s illness will affect other animals. I suggest placing the guppy in a sealed bag and throwing it in the trash, where other animals won’t reach it. Or even cremate it if that’s an option.


Your guppy’s motionless behavior isn’t always a matter of – sleeping or dying. There may be other causes at hand, including constipation, stress, or mild parasitic infections. You may also have deadly illnesses that can spread to other guppies and kill the entire population shortly.

If you notice your guppy displaying lethargic behavior, be thorough about it and investigate the issue. If it’s nothing serious, take appropriate measures and call it a day. But if it is, don’t ignore the problem and act accordingly.

I hope today’s article has shed some light on a more uncommon guppy behavior that can often create confusion among guppy owners.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

Leave a Comment

Your email address will not be published. Required fields are marked *