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Guppies Keep Dying: 6 Easy Steps To Keep Guppies Alive

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I remember how frustrated I was when my guppies kept dying. Over the years, I learned some tricks on how to prevent the guppies from dying. To save you the trouble, I decided to gather it all up in one place to help other people struggling with this topic.

Guppies typically keep dying due to inadequate cycling, in which the tank doesn’t hold enough nitrifying bacteria. That will cause ammonia and nitrites spikes, compromising the fish’s health. However, guppies may also die due to inadequate water conditions, including pH, temperature, and hardness.

As we move forward, I will share a few other reasons that might be behind these guppy deaths. Then, I will take you step-by-step on how to solve the issue. Ultimately, I will show you how to identify a dying guppy fish and what you can do to save it.

Why Do My Guppies Keep Dying?

Guppies have an average lifespan of 2 years. If you keep losing your guppies within days, weeks, or months, these are just a few of the factors you can blame for your predicament:

1. The Water Quality Isn’t Suitable For Guppies

Like most fish, guppies do not appreciate poor water quality. It generates stress in these creatures. If the poor quality of the water persists, the guppies will die. The fish respond negatively to numerous factors, including:

  • Low Oxygen

Guppies will die in a tank with low oxygen levels, especially if the aquarist in question fails to act quickly enough to resolve the problem. The oxygen in a stagnant tank will dissipate gradually until the guppies suffocate.

Guppies suffering from oxygen deficiencies may find refuge at the top or bottom for a while. But unless you add oxygen to the water, the fish will eventually die. 

  • Inadequate Temperature

Guppies require temperatures within a specific range to thrive, typically 72-82 °F (22-28 °C).[1] Hot or cold water will harm them. Don’t assume that the temperature in your aquarium is acceptable simply because the tank has a heater.

Heaters malfunction all the time. They will either raise the temperature or permit it to fall because they have stopped working. 

  • Excessive Water Changes

You have to change the water to keep the tank clean. But large water changes will harm your guppies, especially if the fish are already sick and stressed. The more frequent the water changes, the more harm they will cause. 

If all the dying guppies are new, you can blame significant and regular water changes for the deaths because the transition to a new tank causes stress.

A significant water change can exacerbate that stress, allowing the guppies to either die from the symptoms of stress or fall prey to illnesses that can kill them.

  • Inappropriate Cycling

If the tank isn’t cycled, ammonia and nitrites will kill the fish. You can take steps to neutralize the toxins. But in an uncycled tank, the toxins may spike faster and more frequently than you can react. 

This forces some aquarists to perform the large and frequent water changes mentioned above. However, they don’t realize that they are doing more harm than good.

2. Your Guppies Don’t Eat Properly

With food, you have two concerns that can contribute to the death of your guppies:

  • Starvation

This one is obvious. If you can’t give the guppies regular meals, they will die. Guppies can go without food for five days. But those five days won’t be pleasant. 

Frequently depriving the creatures of food can do lasting damage. Keep this in mind if you’re the sort of aquarist that keeps forgetting to plan for their aquarium’s needs whenever they go on vacation.

  • Overfeeding

Overfeeding is just as bad as underfeeding, if not worse. With underfeeding, the guppies will starve, but only if you can’t feed them for five days or more. 

Overfeeding can kill your fish in two ways. First of all, it can raise the ammonia concentration because guppies in such situations produce a lot of waste. Secondly, it can cause constipation, bloating, and swim bladder disease:

3. The Guppies Are Exposed To Toxins

The biggest threats to most tanks are chlorine and ammonia. Ammonia manifests whenever organic elements in the tank rot. Though, guppies will also exhale some ammonia from their gills. 

Chlorine, on the other hand, enters the tank via tap water. Some locations use chloramine because it is more stable. Unlike chlorine, you can’t eliminate chloramine by leaving the tap water out in the open for 24 hours. Chloramine won’t dissipate on its own. 

4. Genetic Issues Related To Selective Breeding 

Some guppies have weak genetics. They are born with a shorter lifespan. You see this in bright and colorful variants that aquarists created through selective breeding. If all the dead guppies were born in your aquarium, you should start over.

Cull the guppies and buy a brand-new breeding pair. If all the dead guppies come from the same store, you should change suppliers. For all you know, the store’s entire stock of guppies has the same weakness.

5. Your Guppies Are Not Used To The Water Salinity

Most people keep guppies in freshwater tanks. In fact, most people categorize these creatures as freshwater fish. And yet, guppies can survive in brackish water.[2] 

Some aquarists keep guppies in salty water because the salinity enhances their health by making them less susceptible to diseases.

Others use brackish water because they live in areas with a natural supply of salty water. As such, they have no choice but to use brackish water in their fish tanks. This is especially true for fish farms in Asia.

If you transfer a guppy raised in salty water to a freshwater tank, it will die. Unless the aquarium has a cover, the guppy may jump out of the tank to escape the water. 

6. The Guppies Live With Aggressive Tankmates

There are certain species you should avoid when raising guppies. A few examples are Angelfish, Endler’s Livebearers, Barbs, Oscars, Goldfish, Killifhs, and Flowerhorn.[3] As a rule of thumb, one should avoid large fish, cichlids in particular.

If you notice ripped fins and bruises, other fish are probably attacking your guppies. They rarely do this to each other. Bullies will also chase your guppies, exhausting them consistently. This will ultimately weaken their immune system and make them more vulnerable to diseases.

7. Your Guppies Are Sick

If other fish in your aquarium are dying as well, or if the guppies came from the same source, a disease could be involved. Some common illnesses in guppies include dropsy, velvet, fin rot, and flukes.[4]

Sick guppies may become swollen, develop white patches, scratch against objects, swim erratically, and show no interest in food. Some guppies will even appear bent, as happens in tuberculosis:

Pathogens associated with these illnesses include parasites, bacteria, and viruses. These can infect your water and attach to objects and plants. Therefore, healthy guppies coming from a fish store might catch a disease from a previous batch.

How Do You Keep Guppies Alive?

Guppies will only die if you keep them in poorly-maintained tanks. If you act quickly, you can use these methods to keep the guppies alive:

1. Adjusting The Water For Guppies

These are the best water parameters for guppies:

  • Water temperature: 72-82 °F (22-28 °C)
  • Water pH: 6.8-7.8
  • Ammonia and nitrites: 0 ppm
  • Nitrates: <20 ppm
  • Water hardness: 8-12dGH
  • Chloramine and chlorine: 0 ppm

Start by checking the water quality. I personally do that with the API Water Test Kit (link to Amazon). This bundle will accurately measure your pH, ammonia, nitrates, and nitrites levels. I like this bundle because it is easy to use and works quickly.

To measure the chlorine and water hardness, you can go with this 16 in 1 Drinking Water Test Kit (link to Amazon). It will also tell you if other toxins, such as copper, lead, iron, are present in your tank.

If you think the water is too stagnant, check the filter. If the device is still operational, get a more powerful filter. The old one has clearly failed to agitate the water adequately. Better yet, get some pumps and air stones.

Large tanks require multiple pumps and air stones to prevent oxygen deficiencies from becoming a problem. When my tank didn’t have enough oxygen, I simply installed the Hygger Aquarium Air Stone (link to Amazon). Besides being extremely quiet, that device will oxygenate your water within minutes.

2. Picking The Right Guppies Upfront

I highly suggest buying guppies from a source you trust. Where possible, use a local store. If your guppies come from overseas, you can easily receive a guppy that is accustomed to brackish water. The easiest way to eliminate this problem is to buy guppies from a local store.

Don’t forget to review comments from previous customers. These days, it is pretty easy to determine a retailer’s reputation by looking at their previous clients’ opinions online. If a store has a reputation for selling guppies that die soon after arriving in a home tank, look for an alternative store with a superior reputation.

3. Feeding Your Guppies Properly

Guppies are omnivores that eat whatever fish food you can find in a store. That includes flakes, pellets, shrimp, bloodworms, etc. Give them what they can finish in two minutes.[5] As was mentioned earlier, giving them more than that could cause ammonia spikes and constipation.

If you have a history of overfeeding fish, use an automatic feeder. It will feed the guppies the right amount of food. You can go on vacation knowing full well that the guppies won’t starve. 

4. Cycling The Tank For Guppies

As mentioned above, nitrifying bacteria are essential to fish tanks as they prevent ammonia and nitrites spikes. If your tank is new, it probably doesn’t hold these kinds of bacteria. Hence, your guppies will repeatedly die.

Usually, cycling is a natural process that occurs within weeks. During that period, nitrifying bacteria grows primarily on your filter’s media. However, there is a quick way to cycle your tank. You don’t have to wait that long.

You can easily do that by getting the API Quick Start Nitrifying Bacteria (link to Amazon). This product also works great when adding new fish to an established aquarium. If all of this sounds confusing, here is an illustrated Youtube video that will take you throughout the process:

Once you cycle the tank, carry out weekly water changes. I usually recommend 15 to 20 percent weekly changes. Keep a water conditioner on hand to neutralize ammonia, chlorine, and other toxins in an emergency.[6] I typically use the Seachem Prime Water Conditioner (link to Amazon).

If you are not sure how to use water conditioners, here is an article where I explained their purpose and how much of this product you should put in your tank. I also discussed whether you can do this while the fish are still in the tank.

5. Picking The Right Tank 

As a rule of thumb, I recommend keeping the guppies in a large tank. They can’t live in anything smaller than 10 gallons, not happily. Prevent overcrowding by either getting a bigger tank or removing some of the fish.

The tank I chose for my fish is the Tetra Aquarium 20 Gallon Fish Tank Kit (link to Amazon), which I also reviewed here. It comes with built-in features of the high-end aquariums, including a scratch-resistant glass, impressively quiet filter, LED hood, and a heating system.

If your tank is too small, oxygen deficiencies will become a problem, not to mention ammonia spikes.[7] A more affordable option would be picking the right number of guppies for your existing tank. For your convenience, here is an article where I discussed how many guppies should be kept together.

6. Treating Sick Guppies

If you suspect that your guppies are sick, quarantine the fish. That will prevent them from infecting other fish. Then, in the hospital tank, you may use products such as Seachem ParaGuard (link to Amazon). 

Use five m/L (1 capful) of ParaGuard for every 40 L (10 US gallons). You may repeat this dose daily as long as your fish present no signs of stress. Hopefully, over time, you may see the symptoms resolving.

For your convenience, here is an excellent Youtube video that goes through common guppy diseases and treatment methods:

How Do You Know When A Guppy is Dying?

Dying guppies tend to present typical symptoms, such as loss of appetite, lethargy, and rapid breathing. Some guppies will also become pale and start swimming erratically. These signs usually require immediate intervention. Otherwise, the guppy may die.

1. Loss Of Appetite

This is one of the first things to go. Sick and stressed guppies will stop eating. First of all, you will notice that they no longer respond to the food you add to the tank. 

Secondly, the volume of leftovers in the tank will increase, showing you that the guppies have no interest in food. Fish cannot survive without food. If a guppy has stopped eating, it will eventually die.

2. Color Changes

Guppies have beautiful colors. If your guppy is losing its color, you should worry. Sick and stressed guppies look dull.[8] You see this primarily in males, which usually present intense colors to attract females.

3. Lethargic Swimming

Dying guppies will stop moving. Whenever they move, their motions are sluggish. Some guppies will choose to stay at the bottom of the tank, as I discussed in this article.

4. Rapid Breathing

Guppies extract oxygen from the water to survive. They breathe just like humans. However, they don’t breathe open air. One common sign of impending death in fish is labored breathing. 

Because guppies need oxygen to survive, any condition compromises their ability to breathe will kill the creatures. Some guppies will choose to swim at the top, where the water holds more oxygen.

How Do You Save A Dying Guppy?

If the guppy is still alive, you can use the following steps to keep the creature from dying:

  • Perform a partial water change. A water change improves oxygen levels, ejects parasites, reduces toxin levels, and so much more. It can deliver immediate relief.
  • If your guppy is too weak to survive a water change, but the tank has too many toxins, apply water conditioners to neutralize those toxins within minutes.
  • Make sure the guppy is well fed. Add a mixture of animal and plant matter. 
  • Maintain a proper day/night cycle. Guppies sleep in the dark. Leaving the lights on 24 hours a day will stress them because they can’t rest. Remedy the issue by giving them 8 hours of darkness at the end of the day.
  • If the guppy is sick, place it in quarantine and apply the necessary medications. Consult a vet where necessary. Do not assume that every disease can be treated by adding antibiotics. If the guppy was attacked, a quarantine tank could protect the fish from its attackers.

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If your guppies keep dying, the first step would be to determine the cause of death. If your tank is relatively new, it is probably not cycled. You can use nitrifying bacteria to solve that issue. Some products online can cycle your tank within a day.

Next, it would be best to check the water parameters. If you find ammonia levels higher than prescribed, perform a partial water change. If the guppies are still dying, the water changes might not have neutralized all toxins.

Also, make sure that the water doesn’t hold excessive amounts of chlorine or chloramine. Check the pH level to make sure it is in range. If it is too low, partial water changes will help you with that as well.