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Why Does My Guppy Have White Poop? (4 Quick Solutions)

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Guppies are both hardy and beautiful, which makes them a perfect addition to your tank. However, there were times when they got me worried. That includes the time when I saw white stringy poop coming out of my pregnant guppy. To understand the phenomenon, I started investigating the issue quite extensively.

Guppies typically have white poop when malnourished. When they don’t eat properly, the white textured lubricants covering their digestive system are being released into the water. However, guppies may also release white feces due to intestinal parasites, inappropriate water conditions, and old age.

As we move forward in this article, I will share a few useful techniques to treat guppies that extract white feces. That also includes pregnant guppies that might not survive the stressful conditions unless you take action.

Also Read: Guppies Diseases

Why Does My Guppy Have White Poop?

There are many ways to diagnose diseases and illnesses in fish. One of them involves looking at their feces. If it is white and stringy, the guppy is probably unwell. Sometimes, you don’t need the stringy white poop to tell you that your guppy is sick.

That is because the guppy will also manifest other symptoms such as clamped fins, lethargy, and a swollen belly. However, sometimes the guppy is perfectly healthy, not only remaining active but showing no additional signs of illness.

In such cases, diagnosing the white poop can present a challenge. Some potential causes that you should consider in your efforts to identify the source of this symptom include:

1. Old Age

Age is the one factor that people rarely consider. Guppies have an average lifespan of 2 years. Stringy white poop can sometimes manifest in older guppies.[1] While this isn’t always the case, it can happen. If the guppy in question is old, age is the most likely cause.

You may suspect that your guppy has aged if it presents additional symptoms, such as faded colors and weight loss. Old guppies also take frequent naps and sometimes skip their meals. If your guppy is in your tank for over a year and a half, it is most likely old. 

If your guppy is merely old, there is nothing you can do to stop the white poop. Your only response in such a situation is to keep the guppy comfortable by maintaining the tank’s conditions right.

2. Inappropriate Diet

If your guppies are producing stringy white poop, their diet should be your first consideration. After all, the state of a guppy’s poop is directly connected to the food items it consumes. If the poop looks wrong, the creature’s diet is the most likely culprit.

Fish have cells in their bodies that produce mucus. This mucus lubricates the waste generated by the guppy, allowing it to slide out.

You cannot see this mucus coating in most situations because it is obscured by the color and texture of the waste whose appearance is determined by the guppy’s meals.[2]

However, if your fish isn’t eating correctly, you will see this mucus coating because it no longer contains waste. It will take the form of stringy white poop. But where food is concerned, underfeeding is merely one potential cause of this symptom. 

Aquarium fish can also produce white poop as a result of overfeeding. The poop is hard to miss because it trails behind the fish in the water. Overfeeding can cause constipation, a case in which the fish becomes fat and bloated.

3. Intestinal Infection

Once you eliminate age and poor feeding as potential causes, you have to consider the possibility that your guppy has a disease. Intestinal flagellates are a relatively common cause of the white fecal matter. There are also Capillaria worm larvae and Hexamita to consider.[3]

In that case, it would be best if you ensured that the substance in the water is indeed poop. If your fish has tapeworms, you will observe flat segments stretching from the anus that some people might confuse for poop. You might also find these segments in the feces.

4. Stress

Stress can cause a variety of complications in fish, including digestive disorders and diarrhea. Possible causes of stress in guppies include drastic changes in temperature, the wrong pH, high concentrations of ammonia, and harsh lighting, to mention but a few. 

As was mentioned, digestive disorders such as constipation can compel your guppy to produce stringy white poop. Stress won’t directly create white stringy poop in your guppy fish, but it will make it susceptible to digestional diseases.

It would help if you also considered aggressive tankmates and overcrowded tanks. If your guppy can’t establish its territory and live a relatively calm life, it may get sick. Bullying companions will also force your guppy to skip meals, encouraging the mucus lubricants to be extracted as white poop.

Also Read: Guppy Losing Tail, Scales and Fins

How to Treat Guppies with White Poop?

If your guppies are producing white poop, you must identify the cause. That will enable you to deploy the appropriate treatment for your guppy’s situation, for instance:

1. Treating Intestinal Parasites

If the guppy has ailments such as Hexamita and Capillaria, you are encouraged to consult a vet. They know how to treat these diseases without harming the fish. If you are determined to tackle these illnesses yourself, you should first quarantine the fish, especially if you are not confident of your diagnosis.

If the guppy has a disease, you cannot permit it to infect the other fish in your community tank. Once it is isolated, you can start treating it. Metronidazole is one of the most common treatments used in such cases.[4] There is also the option of Albendazole.[5]

You can also use Parinox to treat the water. If those terms are alien to you, I recommend getting the Seachem ParaGuard (link to Amazon). The product is generally safe, and it can do wonders against a variety of parasites.

Depending on your guppy state, a vet might encourage you to raise the temperature by a few degrees and treat the fish to an Epsom salt bath. But if their case is severe, products like Metronidazole are the only practical answer.

However, implementing simple solutions before your remedy arrives could make a difference. For that, I suggest isolating your sick guppy in a hospital tank. Then, raise the temperature so that it is two degrees higher than the original tank.

You may now add one tablespoon of API Aquarium Salt (link to Amazon) for each gallon of water your hospital tank contains. Avoid adding more than that. Otherwise, your guppy may get dehydrated and suffer even more.

2. Ensure High Water Quality

Whenever a guppy falls sick, your first step should be to test the water. Determine whether the parameters are correct. A poorly maintained tank will either make your guppy sick or exacerbate its symptoms.

If you want to increase the guppy’s chances of surviving and recovering, it would be best to improve the conditions in your tank. That means maintaining the right pH (7.0-7.2) and temperature (75-82 degrees F).[6]

That is where I usually recommend getting the API Aquarium Test Kit (link to Amazon). That is a must-have, affordable bundle that accurately measures the pH, ammonia, nitrates, and nitrites in your tank. Getting those parameters right is vital to almost all ailment conditions.

If you find that the pH or the toxins are out of the desired range, I suggest you perform more frequent water changes. That means replacing at least 15-20% of the water weekly. You may replace even more if your tank is relatively crowded or the measured parameters are too dangerous.

3. Feeding Schedule and Amounts

First, try not to overfeed your guppies. Guppies will keep eating as long as you keep feeding them. They aren’t likely to say no to food. That is why you have to control the amount of food you offer them. 

Therefore, it would be best to give them the amounts they can finish in two minutes. If you see leftovers after that period, you’ve probably fed them too much. That could contaminate the water in the long haul, elevating ammonia and other toxins.

It is also imperative that you feed them once or twice a day, no more. Your guppies might act hungry from time to time, even after they have been fed. But you shouldn’t use that as an excuse to keep feeding them.

Underfeeding is just as problematic. If you have a demanding schedule that doesn’t permit you to feed your guppies on time, add an automatic feeder. I personally use the Eheim Automatic Feeding Unit (link to Amazon). 

It is also in your interest to maintain a balanced diet. Provide your guppies with flakes, pellets, live and frozen foods (like shrimp and bloodworms), and vegetables. As omnivores, they eat plants and animals, and their diet should consist of a variety of food items. 

If you have noted symptoms that might suggest constipation, give the fish a few peeled peas. If the constipation was caused by overfeeding, you should force the guppies to fast for a few days before adding peas to their diet.

4. Mitigate stress

Eliminating stressing factors in your tank won’t treat the white stringy poop issue directly, although it might help with gestational infections. My first recommendation here would be to add plants and decorations to your tank.

Providing hiding spots for your guppies will allow them to avoid bullying fish and establish their territories. A stress-free guppy will find it easier to eat and maintain a healthy diet. However, make sure that you do not over-stuff your tank.

I also suggest that you avoid aggressive fish such as cichlids. Those are likely to chase your guppies and nibble their fins. Also, once in a while, it would be best to rearrange your aquarium’s decorations. That will reset territories and lower hostility.

Pregnant Guppies With White Stringy Poop

If your pregnant guppy has a white stringy poop hanging from its tail, it is very likely to be a parasite. That can happen once new fish are introduced to the tank, or when the aquarium’s conditions have deteriorated.

To make sure your pregnant guppy will survive and give birth properly, you should first make sure that the tank is roomy enough and features a heater and a filter. I also recommend testing your water for ammonia, nitrates, and nitrites using a testing kit.

You are also encouraged to add vegetation to the tank. Otherwise, the pregnant guppy may eat the fry. That is true for most fish species. Put a few plants or decorations so that the newborns have enough hiding spots.

Pregnant guppies may also extract white stuff due to the pregnancy itself. In that case, you won’t see a stringy matter hanging from your guppy. You will merely see white floating stuff in your fish tank. However, you have to make sure that it isn’t worms.

If you notice no movements in the white matter, you may leave things as they are. That is especially true if your guppy appears okay and healthy.

However, if you see gentle movements, you should isolate the pregnant guppy and treat your entire tank for worms. Start by consulting a vet for the proper medication.


If your guppy is pooping white matter, you should first consider a parasitic infection. The best way of action here would be isolating the potentially sick guppy and treating it accordingly. You may start with temperature elevation and salt. Then, consult a vet for further remedies.

I also encourage you to improve your tank’s conditions. Measure the water pH, and check for toxins such as ammonia, nitrates, and nitrites. You may also remove aggressive tankmates so that your guppy won’t be susceptible to diseases in the long haul.