Why are my Guppies Dying? And How To Prevent It from Happening?

Guppies are tropical live-bearer fish. Guppies are simple fish to manage and are ideal for beginners. Despite their hardiness, guppies frequently die for no apparent cause. The biggest issue is that most newbies have no idea how to care for guppy fish. As a result, they frequently experience guppies dying in their tank.

There are many reasons behind the death of guppies. Some of them are temperature fluctuations, low pH levels, poor water quality, poor food quality, Ammonia, nitrite and nitrate spikes, aggressive tank mates, stress, guppy diseases, and weak genetics.

Why are my Guppies Dying

This article will help you identify the most common causes of Guppy deaths as well as provide you with some tips on how to keep your pets alive. They will be most beneficial if they are used in accordance with the directions provided below.

What is the Cause of my Guppy’s Death?

There are a lot of elements to consider while keeping guppies in your tank to guarantee that your fish are happy and healthy. Use the things below as a health checklist to figure out what’s causing your guppies’ health problems.

1. Levels of Ammonia, Nitrite, and Nitrate

Guppies are extremely susceptible to ammonia, nitrite, and nitrate level surges, which damage their immune systems and cause them to die soon. Nitrates should be fewer than 40 parts per million in your water, while ammonia and nitrite should both be 0 parts per million. If this isn’t the case, attempt a 25% water change to see if you can get the water back to normal rapidly.

Ammonia can be caused by a variety of reasons, including:

  • Unconsumed fish food decomposes and produces ammonia.
  • If a dead fish is not removed from the tank, it will decompose and raise the ammonia level.
  • A clogged filter can also be a major source of ammonia.
  • Ammonia issues might also be caused by a dirty substrate.

Ammonia is extremely dangerous to your fish. Fish die quickly when their ammonia levels are too high. Even if the fish do not die immediately because the ammonia problem was solved, they will still suffer from ammonia burns. Ammonia burns cause mortality as well, although at a far slower rate.

2. pH Levels that are too Low

Guppies thrive in water with a pH of 7 to 7.8, and anything lower than that makes the water too acidic for them to survive. For optimal results, aim for a pH range of 7 to 7.8 and consider adding crushed coral to their tank. This is one of the safest methods for assisting you in managing their pH levels, especially if you need to correct the levels rapidly.

Ph meter

3. Poor Water Quality

The most common reason for guppies dying in aquariums is poor water quality. By feeding your fish, you are effectively poisoning the water in your tank. Guppies emit waste (poop and pee) into the water source, polluting it. The pollution levels can reach so high that the guppies become drunk and die.

Poor Water Quality

Guppies may expire if there is insufficient oxygen in the water. If the water in your aquarium is too cold or too warm, your guppy fish will perish. Chlorine is poisonous to guppy fish and can be present in tap water. While it is handy to utilize tap water in your fish tank, it must be treated before being used in your aquarium.

4. Tank that hasn’t Been Cycled

So you’ve just set up your first aquarium and put a few guppies in it. After one week, all of your guppies began to perish, and you had no idea why. You did not, however, cycle your aquarium.

You must first cycle your aquarium before adding fish to it. Depending on the size of your tank, the cycling procedure will take 1-2 weeks:

  • Set up your tank and fill it with tank water.
  • Seachem Prime is a de-chlorinator that I use and recommend.
  • Add nitrifying bacteria – the API is what I use and suggest. Start Right Away
  • Wait for the beneficial bacteria to populate the entire tank, which should take around 1-2 weeks.
Tank that hasn't Been Cycled

You may now do a water test using the API Test Kit. The levels of ammonia, nitrite, and nitrate are all monitored. Ammonia and nitrite levels should be zero parts per million, whereas nitrate levels should not exceed 20 parts per million.

You can add fish at this time. Repeat the test one day after introducing the fish to check if the bacteria are able to keep up with the nitrogen cycle. For at least a week, keep an eye on the tank.

5. The Water’s Temperature

Guppies are little tropical fish. They can’t survive in cold water. Guppy fish prefer water temperatures ranging from 72 to 82 degrees Fahrenheit (22 to 28 degrees Celsius). Guppies may survive in water as low as 64 degrees Fahrenheit (18 degrees Celsius), although the danger of disease is high. Guppies should not be maintained in water that is colder than 72°F (22 degrees Celsius).

Maintain Proper Water Temperatures

Guppies are also at risk in warmer water. The oxygen level in the water decreases as the temperature rises. The oxygen content in water exceeding 82 °F (28 °C) can be quite low, and guppies can die from asphyxia.

6. Aggression of Tank Mates

Taking an inventory of your guppies’ tank mates is another helpful option when discovering why they are dying. As a general rule, any fish with long, trailing fins may regard guppies as a threat and attack them, with gouramis and bettas being good examples. Check the tank mates online to make sure they can coexist happily with your guppies, or if changing mates isn’t an option, consider adding more hiding areas to assist your guppies in escape.

Female Guppies are Aggressive

7. Overfeeding

I enjoy feeding and watching my fish eat. I’m sure you like feeding your fish as well. Overfeeding, on the other hand, is quite harmful. Adult guppy fish should be fed once a day or every other day. Overfeeding your fish, much like overfeeding people, can lead to health problems. Overfeeding might result in uneaten meals. As previously noted, uneaten food can contaminate your aquarium and can be a significant cause of ammonia buildup. Do not feed your guppies simply what they can consume in 30 seconds. Repeat the technique several times until you believe they have had enough food.

Is It Possible to Overfeed Guppy Fry

8. Overcrowding in the Fish Tank

Guppies multiply more quickly. Female guppy fish may give birth to 20-120 guppies in a single month. That is why even bigger aquariums with guppies are frequently overrun after a few months. This can result in not just overpopulation but also reduced oxygen levels. The reduced oxygen levels can be lethal to the guppies. That is why it is critical to keep the guppie population under control.

Guppies Tank Mates

You may accomplish this by moving the fish to a different tank or by adding solely male guppies to your aquarium. You will be able to manage the population to some extent as a result of this.

9. Problems with Acclimatization

If your guppies die soon after being introduced to their new tank, you may be dealing with acclimatization concerns. If you float the bag in the water for 30 minutes before introducing it, you have ruled out a temperature problem, therefore you should next check the pH of the water in the tank and the bag.

Problems with Acclimatization

If the difference is greater than.2, begin carefully pouring water from your tank into the bag until it is around 75 percent tank water and 25 percent the water you brought them in. It should be safe to move them to the new tank at this time.

10. Females Under Pressure

If you plan on breeding Guppies, make sure you have the correct male-to-female ratio. This is because men are constantly pursuing females in order to procreate. Females that are hunted repeatedly will exhaust themselves and may succumb to sickness or even death.

11. Genetics of Guppy

Guppies from reputable suppliers should always be considered when stocking your aquarium. Guppies purchased from large pet retailers are frequently of poor quality. They may be colorful, but they may have poor genetics, which can lead to premature mortality.

I’ve had guppies that I bought from huge pet retailers die after only 6 months in my aquariums. Guppies from guppy breeders, on the other hand, can survive for up to 2-3 years. They are more expensive, but their genetics are excellent, and they can produce highly healthy and attractive offspring.

You can choose from the following breeds:

  • Metal guppies
  • Guppies that are albino
  • Guppies from Moscow
  • Guppies with cobras
  • Guppies with grass tails

12. Parasites and Diseases

Guppies can become ill more quickly due to poor water quality and lousy genetics. There are just a few illnesses that affect guppies. Guppies are most commonly infected with ick (white patches on their bodies), velvet (gold dust on their bodies), fin rot, and flukes. Seachem ParaGuard medicine can cure several common guppy disorders. Unfortunately, there are illnesses that are treatable. For example, there are no treatments for guppy fish TB, which is caused by a bacteria called Mycobacterium. Guppies infected with this disease should be removed from the tank and exterminated to prevent the disease from spreading to other guppies.

Guppy Diseases

13. Fry’s Survival Rate Is Low

While breeding Guppies is incredibly simple, keeping the fry alive in some tank designs may be difficult. Guppy fry death is most commonly caused by being eaten by larger fish.

Related Post: Guppies Tank Size: How Many Guppies are in a 5, 10, or 20 Gallon Tank?

How to Determine If Your Guppy Is Dying?

It takes some practice to recognize a sick guppy – at least until you know what to look for. To that end, we’ve created a list of warning indicators that will alert you that there is danger brewing and that your guppies require your assistance. Let’s look at some tell-tale indicators of a sick guppy.

1. Appetite Deficiency

A loss of appetite is one of the first symptoms that anything is wrong. Ideally, you should feed your guppies fish food and veggies twice a day, and there should be no leftover food in the tank. If there is, it might be an indication that your guppies have ich or that you are overfeeding them.

2. Discoloration

When it comes to their health, your guppies are color-coded in several ways. When ordinarily bright guppies begin to lose their luster and become dull, you may have ill guppies in your tank. Discoloration usually signifies illness or stress, and it’s something you should keep an eye out for.


3. Spots

White markings on the body indicate that one or more of your guppies has ich. ‘Ich’ is an abbreviation for Ichthyicphthirius Multifilis, a terrible parasite that is very infectious. You must immediately isolate the diseased fish for treatment, and you will require a medication from your veterinarian.

4. Swelling of the Body

Check to see whether one or more of your guppies are also scabby if they are swollen. If this occurs, your guppy may get dropsy, a bacterial illness that can be fatal. While it is not contagious, you should replace the water because it is now conducive to bacterial growth, and you should isolate and treat the ill guppy.

Pregnant Guppies

5. ‘Bleeding’ Gills

If your guppy’s gills appear to be bleeding when examined closely, this suggests a condition known as ‘gill flukes.’ Affected guppies may also appear to be having difficulties breathing, making this a very visible ailment. You’ll need to go to your supplier and get a drug like Praziquantel so you can start therapy right soon.

Bleeding Gills

How to Prevent your Guppy’s Death?

There are various ‘recommended practices for maintaining guppies that you should observe and build into habits if you want to minimize your fatalities to a minimum. You’ll discover some helpful principles and practices to assist you to cultivate a healthy guppy ecosystem down below.

Cycle Water Before Adding New Fish to Tank Make it a practice to cycle your tank before introducing any new fish. While cycling is a long process (it takes approximately 2 weeks), it is critical because guppies are particularly sensitive to variations in ammonia, nitrite, and nitrate levels. You may guarantee that your guppies are introduced safely into a clean new habitat for the best chance at a new life by arranging ahead of time.

1. Keep Your Tank From Being Overcrowded

A general rule for guppies is two gallons of water per guppy. If you don’t, you’ll have overpopulation and more waste to deal with, and some guppies may suffocate due to a lack of oxygen. If you keep more than 5 guppies per 10 gallons, you will almost certainly have mortality.

Guppies Tank Mates

2. Check that your Tank mates are Compatible

Before introducing a new tank mate to your guppies, always double-check. Even if the store clerk tells you that the fish are compatible, double-check on your phone to be sure. An aggressive species introduced into the tank will swiftly kill your guppy population, therefore it never hurts to obtain a second opinion.

3. Isolate sick Guppies Right away

You should have an isolation tank for emergencies so that if you see a sick fish, you may isolate them and treat them individually while still fortifying and medicating your main tank. A lot of illnesses are very infectious, and the consequences may be severe if you don’t act quickly.

You’ll have a greater chance of saving all of your fish if you isolate any ill fish soon away.

4. Maintain a Consistent Temperature

Fish are extremely temperature-sensitive, and simply having a water heater does not guarantee that everything will be well. Take care when positioning your tank to avoid any ambient factors that might affect the performance.

Maintain Proper Water Temperatures

5. Feeding Techniques

Feeding your guppies high-quality, varied food will undoubtedly increase the lifespan of your fish. You can feed your guppy fish commercial food, but stick to well-known brands like Tetra. Flakes, vegetable pellets, spirulina pills, freeze-dried brine shrimp, tubifex, or blood worms can all be fed. You may create food for your guppies at home if you have the time and desire. You may grow live foods like daphnia, brine shrimp, and vinegar eels. 

6. Regular Water Changes

Regular water changes are also important in maintaining the health of your guppy fish. Toxins that are detrimental to your guppy fish can be removed from your tank by changing the water. You do not need to perform extensive water changes. Once a week, I recommend replacing 20-30% of the water. If you want to maintain your fish healthy and lengthen their lives, don’t be lazy and miss water changes.

Changes Water Quality

7. Tank Routine Maintenance

Depending on the size of the filter, it should be cleaned once or twice a month. Simply rinse your sponge filter in aquarium water if you have one. Cleaning it with tap water will destroy the good microorganisms.

fish tank maintenance

Apply the same logic to internal and external filters. Use aquarium water to rinse the sponge and biological filter material. If you want to maintain the colony of beneficial bacteria intact, don’t expose them to air for too long, and don’t allow them to dry up. Vacuuming your tank’s substrate at least once a month is also a good idea. Every time you replace the water, if possible, vacuum a little bit. This will assist in the removal of a significant amount of mock, which is a significant source of ammonia. It is not required to clean the glass of your fish tank once a week, although it is recommended for aesthetic reasons.

8. Prevent or Battle Sickness as soon as Possible

The most efficient way to combat diseases is to prevent them. However, your fish may fall unwell from time to time. It is vital to start treatment for that specific condition as soon as you notice any symptoms of a problem. Early detection and treatment may save your fish’s life. Remove the sick guppy fish from the main tank and, if necessary, place it in a quarantine tank. Quarantine additional fish or plants before introducing them to your previously established, disease-free guppy aquarium. Keep your new plants or guppies in a quarantine tank for two weeks and, if required, treat them for parasites.

9. Keeping the fry Safe

The first option is to separate the fry from the adults. To do this, we recommend transferring the fry to a different tank. Then you may let them develop until they are large enough not to be eaten by the adult fish in the original tank. You should also transfer any fry that is developing considerably quicker than the rest as the larger fry may ultimately feed on their younger siblings.

Guppy Fry Grow Faster

We’ve found that floating plants like Horn wort and Java Moss work well for us. Make sure you place some at the top of the tank because the fry tends to hang around on the water’s surface, which exposes them to being eaten. You should also feed your adult and fry regularly. This will not only keep the adults from eating the fry (since their stomachs will be full), but it will also help your baby develop more quickly.

Frequently Asked Questions

What’s the Deal With my Male Guppies Dying?

Check your pH, then ammonia, nitrite, and nitrate levels. 6.8 to 7.8 is the most comfortable range, however, 7 to 7.8 is optimal. Ammonia should be zero, nitrites should be zero, and nitrates should be fewer than 40 ppm. If this is not the case, a 25% water change will assist to equalise the levels.

What’s the Deal With my Female Guppies Dying?

When only female guppies die, the tank may have too many males. Maintain a two-to-one female-to-male ratio so that male guppies eager to procreate have more than one target to harass.

The Bottom Line on Why are my Guppies Dying?

Once you’ve gotten acclimated to them, guppies are really simple to care for. Just remember to perform a 25% water change every 1 to 2 weeks to ensure that your water quality remains ideal. Don’t forget to provide them with a variety of foods. It’s a good idea to cycle their tank and isolate and treat the newcomers for sickness before introducing them to their new surroundings and exposing them to their new environment. Apart from that, make sure they eat a nutritious, varied diet that includes live food and veggies on occasion, and that their water is checked on a regular basis.

Take advantage of the advice we’ve given you today, and your guppies will be well in no time.

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