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Why Did My Guppies Die? – The Most Common Causes!

If you have an aquarium, you are probably already used to the idea that your fish will die at times without explanation – and if you aren’t yet used to this idea, you are probably new to the hobby.

However, even for experienced hobbyists who are accustomed to losing fish occasionally, it’s frustrating and upsetting, and you might be wondering, why did my guppies die? If so, we’re going to look at that today.

There are a great many things that can kill off guppies, as these are unfortunately not a particularly robust species, and they will die if the conditions aren’t right for them, no matter how hard you try to save them.

Understanding what can go wrong should help you to rescue your fish and reduce the risk of more dying, or prevent them from dying in the future, but it isn’t always easy to anticipate what might kill them, so let’s find out.

Remember that you should always remove dead fish from the tank, and not leave them in there, as it may make the situation worse and kill off other fish.

If you act quickly when you see your guppies dying, you may be able to save your fish, but be aware that it might be too late – because guppies are delicate, so it may have gone too far before you even notice the problem.

However, it is still worth trying, so let’s find out what kills guppies.

Why Do Guppies Die So Easily?

Guppies were once known as quite a hardy species that wasn’t particularly easy to kill, but unfortunately, mass breeding and attempts to create fancy-looking variations within the species have led to a lot more weakness among the fish, and they are considered a fairly sensitive breed now, with much shorter lifespans.

It is important to bear that in mind when you consider whether to get guppies or not, and if you are an inexperienced hobbyist, you might want to try an easier species first. Choose a reputable seller with good reviews so you know that the fish are healthy when you get them.

Your guppies will be quite sensitive to all sorts of problems, including things like changes in the water, temperature fluctuations, poor water quality, lack of cycling, overfeeding, overcrowding, bad genetics, parasites, diseases, and more.

You need to carefully regulate the water quality and the conditions that your guppies are kept in if you want the fish to thrive.

You should keep an eye on your guppies any time you make a change to the tank, and regularly check how lively they are, or whether they are showing any signs of disease.

If you notice any problems, you need to act promptly if you are to have any chance of saving the fish.

How To Tell If Your Guppy Is Dying

A few key signs may warn you that one of your guppies is dying, and these include things like discoloration (your fish may start to look dull or pale), or the development of white spots on the body, which is a sign of ich.

If you see spots, you need to isolate the fish immediately to reduce the risk of it spreading the ich to others, and you’ll need to get medication for the afflicted fish.

You should also look out for any swelling on your guppy’s body, as this suggests that the guppy has an infection.

If it is also scabby, it may have dropsy, which will encourage bacterial growth in the water, so you will need to change the water and isolate and treat the fish.

Swelling is not a good sign, especially when combined with scabs, so keep an eye on this and compare your guppy to the other guppies to check whether it is swollen.

Another sign that something has gone wrong with your fish is if it stops eating and shows no further interest in food.

Alternatively, bleeding gills might indicate that your fish has something called “gill flukes,” which may make it hard to breathe.

Any of these things could indicate that your guppy is in danger of dying, and they all require you to pay attention and treat the fish or improve its conditions.

Why Are My Male Guppies Dying?

It isn’t always clear why male guppies die, although some owners do report this phenomenon, where all the male fish suffer from some unknown affliction and eventually die, while the females and young guppies survive.

Sometimes, males will die due to genetic conditions or something in the water, but questions about whether any diseases affect only the males do not yet have any clear answers, and people are still unsure what causes mass death among the males.

If you have had this happen, try quarantining any remaining males, and see whether they recover or not.

You should also change the tank water and watch out for physical symptoms that might give you some clue about what is affecting the males.

If you lose all of the males, spend some time cleaning and disinfecting the tank, and then introduce new males from a different source and a different breeding line to minimize the risk of the problem recurring.

If you have recently bought the males and they all seem sick, it is quite likely that they were sick before you got them, as many stores do not have particularly good conditions for their fish and may keep them in an environment that leave the fish stressed and unhappy.

You should try to choose a seller that has a good reputation, and check whether the fish seem healthy and lively before you purchase them.

Why Are My Female Guppies Dying?

There are things that can kill only your female guppies, and if you have an imbalance of males and females in the tank, this is one reason that the females might start dying; the males will sometimes over-mate them and cause them to die from stress and exhaustion.

If you see the females in your tank getting harassed, you should step in and remove some of the males so that the females can have a break, get enough to eat, and rest. This should reduce the risk of them getting over-mated by the males.

Female guppies may also run into problems with giving birth, which often results in death for the fish.

This is again a problem that has resulted from over-breeding and genetic weaknesses in the fish, and more and more breeders are starting to notice it in their shoals.

It is particularly common in older females, especially those that are overweight, and as guppies are increasingly bred to be large, it can be a serious issue.

If you are having a lot of problems with your female fish dying, consider trying a different supplier, as you may be encountering a weak strain or one that is particularly susceptible to diseases.

As always, you should check your tank parameters and ensure that the temperature is right before you assume that the weakness is within the fish, but the more overbred and flashy your females are, the less likely they are to be healthy.

Why Your Guppy Fry Are Dying!

It is quite common for fry to die, especially when they are first born, so you don’t need to worry too much when this happens, as long as you aren’t losing all of the babies.

Sometimes, the parents will consume the fry, which can result in a high death rate, so you may wish to separate the fry from the parents if you are able to do so.

However, the main reason that fry often die is improper tank conditions; lack of oxygen or high levels of toxins can cause this kind of issue.

Your fry need a good amount of oxygen in the water if they are to survive, and they may not be able to swim into the oxygen-rich areas if they are already struggling.

If you see the fry gasping and trying to swim toward the surface, it’s likely that the tank does not have enough oxygen for them.

Unsuitable temperatures could have a big impact on the guppy fry too; guppies are warm water fish and they will struggle if the temperature drops below 72 degrees F or climbs above 79 degrees F. Sharp temperature fluctuations will also kill the fry.

High chlorine levels will decimate fry and could wipe out the whole bunch, and will kill many adult fish too.

Do Guppies Die After Giving Birth?

A healthy guppy should not die after giving birth, but many guppies do, unfortunately, and you might find that your pregnant females struggle to survive when they have given birth, especially if they have had a large brood or if the water is not well suited to them.

The more stressed your female fish are, the more likely they are to die as a result of giving birth, so make sure that the conditions are as suitable as possible and stop the female from being harassed by the males.

You should check the water quality and the temperature when you think one of your females is getting ready to give birth, and make sure that these are as good as they can be.

The more stable the tank is, the happier the fish are likely to be, and the less likely they are to die.

If a female is old or already suffering from some health conditions, pregnancy will often be too much for her body, and you may find that this kills her off.

This is one of the reasons that it’s worth knowing your individual guppies and approximately how old they are (if you can) so that you’ll know this is a likely reason if a female does die.

Why Is My Guppy Dying At Bottom Of Tank?

Guppies often retreat to the bottom of the tank when they are stressed, and stress is frequently followed by death, so you should check whether anything is going wrong in the tank to cause stress – such as overcrowding, sickness, high waste levels, toxins, or low oxygen levels.

The more your fish lies at the bottom of the tank, the more likely it is to die, because this positioning indicates that it lacks the energy to swim, feed, and interact with other fish as it should.

Remember that fish constantly expend energy when they are swimming around in the tank, and if one of your guppies is constantly lying near the bottom, it’s likely because it no longer has energy to spare.

You may also find it hiding in the weeds near the bottom, as it will feel safer from predators here. Usually, by the time a guppy is behaving like this, it’s very sick.

The commonest things that would cause your guppy to die near the bottom of the tank are environmental factors, such as poor water quality, disease, and improper temperature.

You should check all of these parameters, especially if you have multiple guppies lying at the bottom of the tank and looking sick.

Why Are My Guppies Dying One By One?

If your guppies are dying one at a time, rather than all at once, it is more likely that a disease is spreading through the tank, rather than because the fish are suffering from a problem with the environment they are being kept in.

You should check whether any of them are showing signs of illness or infections, and whether this could be gradually spreading throughout the shoal, slowly killing off the fish.

If you have recently added any new guppies to your tank, it’s quite likely that you unintentionally introduced a disease at the same time, and your guppies are dying because this disease has spread through the tank; this can happen even if the guppy you added seems healthy, as it may have developed some resistance to the disease that the other guppies do not have.

You should be very careful when you add any fish to your tank, because they will often introduce diseases that your stock does not yet have any immunity to.

If your guppies are dying one by one, make sure you remove the dead or sick fish and inspect them for signs that might tell you what is causing them to die.

Look for bacterial and fungal infections, inspect them for swelling, and check whether you can see anything else that indicates what caused the death.

You might want to consult with a local expert to see if you can find out what’s going wrong, as they might recognize signs that you are overlooking.

Why Are My Guppies Dying But My Other Fish Are OK?

If only your guppies are dying, it will be either because they are the only fish in the tank that are vulnerable to a particular kind of disease that has been introduced, or because something about the environment is upsetting them but not your other fish.

This might be the case if your other fish species are hardy and more tolerant of changing conditions.

You should test the tank water if your guppies are dying, and see if one of the levels has got out of balance. An overcrowded tank could also cause major stress in your guppy population, leaving them struggling to survive.

Alternatively, you may have added a species that is compatible with all the stock except the guppies. You should check whether any recent additions are likely to be upsetting your guppies and preventing them from feeling safe in the aquarium.

Why Are My Guppies Dying Suddenly?

If your guppies are dying very suddenly, the first thing that you should do is check the water temperature to see if it has changed. Sharp fluctuations, a drop, or a spike could all cause issues for your fish.

You should pay a lot of attention if fish are dying without warning, because it usually means something dramatic has changed within the tank. A high level of chlorine is a common cause of death among guppies, and it is easy for chlorine levels to spike if you use tap water for your fish.

The tank cycling badly may also cause death among your guppies, and is something else that you should keep an eye on. Do regular water tests so you notice any sharp changes.

Can Guppies Die From Overfeeding?

Guppies can die from being overfed, yes. They are very heavy feeders, and they will eat as much food as you give them.

Unfortunately, eating too much can cause bloating among the fish, and this may result in them getting sick and dying. A fat guppy is not a healthy guppy, so try to avoid overfeeding your fish.

Another issue with overfeeding is that it causes a buildup of waste in the tank, which can lead to a rise in ammonia levels. This will also kill your fish, so it’s important to carefully regulate the amount of food you give your fish.


If you have ever asked “why did my guppies die?” you should now have several answers as to what happened; anything from water temperature to toxins to diseases can kill guppies. Investigate all of the causes listed above to try to figure out what went wrong with your fish so that you can save the rest of them, or prevent future shoals from dying. Guppies are not the easiest fish to keep, but with the proper care and attention, they should survive.