Guppies are live-bearer tropical fish. They are popular among aquarium owners due to their vibrant colors and peaceful nature. Guppies are very easy to keep fish and are great for beginners. Although they are very hardy, often guppies keep dying for no obvious reason.
The main problem is that most beginners have no clue regarding how to keep guppy fish. Therefore, they often face the problem of guppies dying in their aquarium.
I’ve created this article to help beginners figure out why their guppies are kept dying and what to do about it. I’ve also written a complete guide on how to care for guppies, where I talk about the biggest challenges of keeping guppies.
Reasons why Guppies are Dying
I will now highlight the reasons of guppy fish die in your aquarium.
1. Poor Water Quality
The most common reason for guppies dying in your aquarium is the poor water quality. By feeding your fish you actually pollute the water in your tank. Guppies produce waste (they poop and pee), which is polluting the water. Over time the pollution can become so high, that the guppies will get intoxicated and will die.
The lack of oxygen in the water can also cause guppies to die. Putting too cold or too warm water in your aquarium will cause death to your guppy fish.
Tap water contains chlorine, which is deadly to guppy fish. Though using tap water for your fish tank is find, but need to be treated before adding it to your aquarium.
2. Non-Cycled Tank
So you just started you first aquarium and you added some guppies. After one week, all your guppies started to die and you have no idea why that is happening.
Well, you did not cycle your aquarium.
Before you add fish to your aquarium, you have to cycle it first. The cycling process will take 1-2 weeks, depending on the size of your tank:
- Setup your tank and put add tank water into it
- Add de-chlorinator – I use & recommend Seachem Prime
- Add nitryfing bacteria – I use & recommend the API Quick Start
- Wait about 1-2 weeks for the beneficial bacteria to colonize the entire tank
At this point, you can perform a water test with the API Test Kit. You test for ammonia, nitrite and nitrate. Ammonia and nitrite should be at 0 ppm, while nitrate can be at a maximum 20 ppm.
At this point, you can add fish. One day after adding the fish, perform another test to see, if the bacteria can keep up with the nitrogen cycle. Keep monitoring the tank for at least one week.
3. Raising Ammonia Level
Ammonia level in the fish tank should always be at 0 ppm. That said, there should be no ammonia present in your aquarium. The nitrifying bacteria should turn ammonia right away into nitrites and then into nitrates. This is the nitrogen cycle, which I explained above.
- Ammonia can be caused by multiple factors:
- Uneaten fish food will decompose and will turn into ammonia
- Dead fish which is not removed from the tank will decay and will increase ammonia level
- Dirty filter can also be a huge source for ammonia
- Dirty substrate can also cause ammonia problems
Ammonia is very harmful for your fish. High ammonia level usually results in instant fish death. If the fish do not die instantly, because you were able fix the ammonia problem, they will still get ammonia burns. Ammonia burns will also result in death, but at much slower rate.
I love feeding my fish and watching them eat. I bet you also like feeding your fish. However, overfeeding is very dangerous.
You should feed your adult guppy fish once a day or once every other day.
Feeding too much food to your fish, can cause health issues; just like with humans.
Feeding too much can result in uneaten food. As stated above, uneaten food will pollute your aquarium and can be a huge source for raising ammonia levels.
Do not feed your guppies only the amount they can eat in 30 seconds. Repeat the process few times, until you think they got enough food.
Check out my guppy feeding / food guide, where I share a magic homemade fish food receipt, that will boost guppy growth rate significantly.
5. Overcrowded Fish Tank
Guppies reproduce at a faster pace. In a single month, female guppy fish can give birth to 20-120 guppies. That is why; it is pretty common that even larger aquariums with guppies can get overcrowded within a few months.
This can lead to a problem of not just overcrowding but lower oxygen levels. The lower oxygen levels can prove to be fatal for the guppies. That is why it is always important to control the population of guppies.
You can either do so by shifting the fishes to a separate tank or introducing only male guppies to your aquarium. This will allow you to control the population to a certain extent.
6. Water Temperature
Guppies are tropical fish. They cannot survive in cold water.
Guppy fish prefer water temperature between 72-82 °F (22-28 °C ). Guppies can survive in water with temperature as low as 64 °F (18 °C), but the chances of diseases are very high. I don’t recommend keeping guppies in water colder than 72 °F (22 °C).
Warmer water is also dangerous for guppies. As the water heats up, the oxygen level of the water lowers. In water with a temperature over 82 °F (28 °C) the oxygen level can be very low and guppies can die due suffocation.
7. Poor Guppy Genetics
When you are populating your aquarium with guppies, you should always consider guppies from trusted sources.
Guppies you will buy in big pet stores are usually the lowest quality. Although they are colorful, they might have bad genetics, which can lead to early death.
I’ve experienced myself with guppies that I bought from big pet stores do not live for more than 6 months in my aquariums.
On the other hand, guppies which come from guppy breeders can live up to 2-3 years. Sure, they cost more, but their genetics are very good and can also produce very healthy and beautiful offspring.
Some of the breeds which you can opt for are:
- Metal guppies
- Albino guppies
- Moscow guppies
- Cobra guppies
- Grass tail guppies
8. Diseases & Parasites
Due to bad genetics and poor water quality guppies can get sick quicker. There are few guppy-specific diseases. However, the most common diseases which guppies get are ick (white spots on their body), velvet (gold dust on their body), fin rot, and flukes. These common guppy diseases can be treated with the Seachem ParaGuard medication.
Unfortunately, there are diseases, which can be treated. For instance, guppy fish tuberculosis, which is caused by a bacteria called mycobacterium has no remedies. Guppies affected with this disease should be removed from the tank and destroyed to stop spreading to the other guppies.
You can read more about guppy diseases and illnesses in my other detailed article.
How to Keep Your Guppies Healthy?
In the next part I will highlight some of the things you can do to keep your guppies healthy and avoid them dying very early.
1. Proper Feeding
Feeding your guppies quality and a variety of food will definitely contribute to the life-span for your fish.
You can feed your guppy fish commercial food, but try to use food from well-known brands, such as Tetra.
You can feed flakes, veggie pellets, spirulina tablets, freeze-dried brine shrimp, tubifex or blood worms.
If you have the time and the will, you can prepare food for your guppies at home. You can cultivate live food such as daphnia, brine shrimp or vinegar eels.
2. Regular Water Changes
Doing regular water changes is also a key factor when it comes to keeping your guppy fish healthy.
By changing the water in your tank you will remove the toxins that are harmful to your guppy fish.
You don’t have to do big water changes. I recommend changing 20-30% of the water once a week.
Don’t be lazy and don’t skip on water changes if you want to extend the life of your fish and keep them healthy.
3. Regular Tank Maintenance
Depending on the size of the filter once or twice a month it is necessary to clean it.
If you have a sponge filter, just rinse it in aquarium water. Do not clean it in tap water, because you will kill off beneficial bacteria.
Do the same with internal or external filters. Rinse the sponge and the biological filter media with aquarium water. Don’t expose them for too long to air and don’t let it to dry out, because you want to keep the colony of beneficial bacteria intact.
It is also good to vacuum the substrate of your tank at least once a month. If you can, do some minor vacuuming every time you do a water change. This will help removing a lot of mock, which is a huge source for ammonia.
Cleaning the glass of your fish tank is not necessary but for the looks, you should do it once a week.
4. Prevent or Combat Diseases Fast
The best way to combat diseases is to prevent them. However, occasionally your fish can get sick.
It is important to start the treatment for that particular disease as soon as you see any sign of a problem. Early treatment can save your fish’s life.
If necessary, remove the sick guppy fish from the main tank and add to a quarantine tank.
Before adding new fish or plants into your already established, disease-free guppy aquarium, quarantine them. Keep your new plants or guppies for 2 weeks in a quarantine tank and if necessary treat them for parasites, just to be safe.
Wrapping it up
I really hope that this article has helped you to stop your guppies from dying.
If you still have any questions and can’t figure out why your guppy fish keep dying, please leave a comment below or send me an email describing your tank setup. I will try to help as quickly as possible to save your beautiful guppy fish.