Guppy Diseases, Symptoms, and Remedies

Dropsy on Guppy Fish

Guppies might be active and friendly but they’re also prone to many diseases. Like every other fish, guppies also need proper care and guidance if you’re planning to keep them as pets.

And if you’re not too careful, these deadly diseases wouldn’t take much time to take the lives of these poor guppies.

These hardy fishes are popular among amateur fish-breeders not just for their beauty but also for their hardy nature. And since they’re able to survive different water temperatures and pH levels, they’re probably the ones to keep. However, even the tiniest mistake in fish-keeping would let them fall sick.

Common Guppy Diseases, illness and Cure

Here are some common diseases that guppies might suffer from, their symptoms, cause, and remedies.


Stress is a major factor that causes guppies to suffer from other major diseases. Stress can be really very harmful to guppies, especially since they’re peaceful fishes, they don’t deal well with it.

Stress can lead to a weaker immune system resulting in becoming vulnerable to more parasites and infections. Therefore, it is important to take care of your guppies and reduce their stress levels as much as possible.


There are a lot of factors that cause stress among guppy fishes. These tiny fishes are social animals so they need to be in groups to survive. And if they’re left out alone, they’re very likely to be stressed.

Another major cause can be a lack of hiding place. These peaceful fishes do not gel well with aggressive ones. And they’re also not very fond of an “LINK“over-crowded fish tank”LINK“. Hence, they need a coup of their own to deal with a lot of such situations. So, when an aquarium doesn’t have enough hiding place, it increases the level of stress for guppies.

Another reason might be the water in the aquarium. Even though the guppies have the ability to survive in different temperatures and pH levels, it’s not always possible that they make it. And if your aquarium has dirty water, then there are higher chances to increase stress and illness in guppies.


The perfect remedy to avoid stress in guppies is to have a tank filled with a few of them. The guppies will have friends to rely on. Get real plants and in abundance if you have guppy fishes as pets. The more hiding place they have, the less stressed.

Make sure to pair your guppies with fishes that are calm and peaceful like themselves. Aggressive fishes in a tank can also cause guppies stress. And its crucial to have a proper water condition for guppies to thrive. Make sure to keep the water temperature balanced and change the water on a regular basis.


Hexamitiasis – Hole in the head or body

Hexamitiasis or hole in the head or body is caused by protozoan parasite called Hexamita. The diseases might be rare, however, it can be very troublesome if guppies suffer.

The guppies infected with hexamitiasis tends to lose its appetite. And at one point, they’ll stop eating all together. They turn pale and produce white, stringy faeces.

What are the causes:

Hexamitiasis is usually caused by inadequate filtration, especially in overstocked aquariums. Another cause might be lack of changed water and oxygen.

How to treat Hexamitiasis:

the best remedy for Hexamitiasis is medicated food. The guppies lose their appetite when infected so you can apply the medication to the water as well. It is usually treated with Metronidazole (Flagyl).

Flukes (Gill Flukes/Worms)

There can be tiny white worms in an aquarium that can cause fluke or gill worms in your guppies. These tiny worms are visible with naked eyes. And when a guppy gets infected, their gills tends to bleed. The worm causes the fish to gasp for air at the water surface or be at the bottom of the aquarium.

The guppies can be seen trying to rub their gills against rocks or decorations constantly. And it’ll be hard for them to breed.

What are the causes:

Usually, fluke occurs when you introduce a new plant or fish into the aquarium. And another main cause is the poor quality of water. Poor quality water help fluke multiply more rapidly.

How to treat Flukes:

The best thing to do to prevent fluke is to keep the new fish or plants in quarantine. It helps prevent them from spreading any diseases or parasites.

Also, keeping the water condition proper is very crucial. It helps prevent the fluke to grow and multiply.

But by chance, if your guppies do get gill flukes/worms, there are plenty of medications available to treat them. However, the problem with fluke medication is that they might require a few treatments at the same time. The medicines available usually only cares about hatched flukes and not their eggs. So, it’s important to get the procedure right.

Fin and Tail Rot

Fins rot is a pretty common disease with a lot of freshwater fishes. And since guppies are one of them, they’re also prone to it.

What are the causes:

There are two main causes of fin and tail rot in a guppy fish; bacterial infection and fungus. And its important to know what is the main cause because they’re both treated differently.

If the tail and the fin isn’t damaged but there are signs of rotting, than it is from bacterial infections. And if both the fin and tail is damaged and is rotting, than it is a fungus growing on the nipped fins.

Another factor causing the fin and tail rot might be poor quality water and ammonia burns.

How to treat Fin and Tail Rot:

The best thing to do to cure rot is by separating the sick fish from the regular tank and placing them in a quarantine tank.

If its rot caused by fungus, there are special medications available. Always follow the instructions as given by the vet.

If it’s bacterial infection use antibiotics like Seachem ParaGuard, Maracyn, Maracyn 2, or Tetracycline.

If it’s ammonia burns, make sure that you clean the water and keep your fish in high-quality water.

Ichthyophthirius (White Spots/Ich)

Ich, also known as the white spot disease is a parasitic disease that occurs in many guppies. It affects the gills of the fish reducing their oxygen intake and respiratory function.

Ichthyophthirius Multifils is a kind of parasite that creates while lumps in the guppy’s body.

Ich makes guppies itchy and they look for places to rub their bodies against. The guppies might lose their appetite. And they form tiny white spots on their skin and around their fins.

What are the causes:

Ich is usually caused by an imbalance in the water temperature and pH level. They also come from dirty, poor quality water infecting the fishes in your tank.

How to treat White Spots / Ich:

The best thing to do to avoid guppies to catch Ich is cleaning the tank on a regular basis. Make sure that the water parameters match the guppies’ requirement. And use chemicals like Malachite Green or Formalin to kill the parasite.

Consult a vet as soon as possible to avoid the ich from spreading. Use the medication as recommended by the vet. Apply aquarium salt even after removing the guppies in tank where they fell sick.


Dropsy is a common disease that affects guppies. It gives swollen bellies to the guppies and they lose their appetite. They also start forming loose and unstructured scales.

What are the causes:

Dropsy is caused due to fluid build-up inside the body. The bad bacteria and poor quality food is what gives rise to this disease. It infects the liver or kidney of the guppy that causes the abdomen to fill with fluid.

The main cause of dropsy is feeding blood worms or long high stress.

How to treat Columnaris and Mouth Fungus:

In order to cure Dropsy you need to get proper guidance from an expert as soon as possible. As the disease is spotted at a pretty late stage, it’s better to take precautions.

However, if guppies do get dropsy, you should immediately separate them from the tank to stop them from spreading it to others. Place them in a safe and separate tank and do as the doctor tells you.

Piscioodinium/Velvet (Oodinium)

Piscioodinium also known as velvet (oodinium) is somewhat similar to ich. But unlike ich, it is a rare disease and the symptoms are hard to notice at an early stage.

The guppies develop a gold-colored dots all over their body when suffering from velvet disease. However, it is a highly contagious disease that takes no time to spread.

What are the causes:

Velvet is caused by a tiny parasite named Oodinium. These tiny parasites latch onto the gills, fins, and the body of the guppies.

The parasite usually spreads in an aquarium by contaminated tools, fish, or the tank itself. It might also cause due to frozen live foods containing dormant forms of the species.

How to treat Piscioodinium/Velvet:

One way to mitigate the reproduction of velvet is using sodium chloride. However, just using salt is not enough to completely stop the outbreak. Therefore you can use common medications like methylene blue, copper sulfate, malachite green, formalin, and acriflavin.

Another way to prevent the spreading of parasite is by leaving the tank in total darkness for at least seven days (or till the disease is eradicated). Velvet parasites tend to derive energy from photosynthesis. And by turning your tank dark stops the process.


Leeches commonly sucks the blood off of guppies. These parasites suck on the blood of the fish as long as they’re not full.

Though leeches might not be a bigger problem, however, the loss of blood can be fatal for tiny guppies.

What are the causes:

The biggest possibility for leeches to enter a guppy fish tank is through decorative, submerse aquatic plants. Pre-owned aquarium equipment, substrate, and decorations can also cause leeches to enter the tank.

How to treat leeches:

There is a very specific way you can get rid of the leech from sucking the blood out of the guppies. You can try pulling it off by grasping the parasite from guppy’s body. But that might cause regurgitation leaving parts of leech’s jaw still attached to the body.

So, use a fingernail to break off the seal at both ends of the leech. Aim at the oral sucker. First, start at the smaller end, gradually progressing towards the larger end. And as soon as the sucker seal breaks off, the leech will immediately detach itself.

Anchor Worms

Anchor worm, also known as Lernaea is a parasite that’s frequently found in fresh water fishes. They belong to a genus of copepod crustaceans.

Guppies that have anchor worms are frequently rubbing their bodies. You can spot redness in their bodies and it gets hard for them to breathe.

The guppies get inflammation on their body and small red or white-green worms can be seen in the wound.

What are the causes:

During mating, the female hides into the flesh of a fish turns into a worm like form. They mostly get into the tank if you introduce a new fish carrying the worm into the tank.

Another major cause is bringing in live plants into the aquarium. It might not be always necessary, but live plants do carry a lot of bacteria and parasites. So, there is a possibility of live plants bringing in anchor worms into the tank.

How to treat Anchor Worms:

Potassium permanganate is considered one of the best remedies of anchor worm. It can either be used as a tank treatment or a dip treatment.

You can also use other forms of treatments like formalin dip or salt dip. Even modern antiparasitics can also work.

Another way to get rid of anchor worm is by manually removing the parasite from the fish’s body. Hold the fish in the hand and remove the parasite that is visible with eyes with a tweezer.

Fish Lice

Fish lice, also known as Argulus belongs to the same family as the anchor worm. It is also a copepod parasite that leeches onto the body of a guppy.

But unlike the anchor worm, lice are a bit hard to detect. These parasites hides into the guppy’s body camouflaging themselves in the color of the fish. So, they can be tricky to spot and remove.

But you can see guppies rubbing their bodies against hard decors if they’re infected with lice. Fish lice can cause a severe inflammatory reaction in the fish. And it can lead to different other viral, bacterial, and hemoprotozoal diseases.

Camallanus Internal Worm

Camallanus Internal Worm is one of the most common parasites you can find affecting a guppy fish. These parasites have a length of up to 0.8 inches and they stick out from the anus of the guppy fish.

They’re brown or orange in color and easy to detect and separate from waste.

What are the causes:

There is no known cause of camallanus worm. But it’s said that guppies that live in an outdoor pond usually affected by these parasites. Breeders also claim that feeding Cyclops to guppies cause camallanus internal worm in guppies.

How to treat Camallanus Internal Worm:

An easy remedy for camallanus is Levamisole (Ergamisol). Make sure to apply it for at least five days. You can also opt for Fenbendazole or Parcide X or D as an alternative to Levamisole.

Make sure to vacuum the substrate and clean the filter entirely after applying the remedy. Also, don’t forget to change the water (about 70-90% of it). And most importantly, avoid feeding Cyclops to your guppies.


Protozoan parasite might be harmful to most of the fishes. But guppies are most likely to be affected by it. These parasites stick themselves to the skin of the guppy and slowly and steadily enters their body.

The protozoan enters the fish’s body through their muscle and reaches the bloodstream.

What are the causes:

The protozoan parasite usually develops when the tank isn’t properly cleaned. Bad water quality can easily give rise to protozoan. But one of the major cause has to be unheated tanks.

How to treat Protozoan:

The best thing to avoid protozoan parasite is to keep a heater in your tank. And keep the water temperature stable. Clean the water as much as possible, do partial water changes and use filter at all times.

You can also use Formalin or Malachite Green to cure the disease in an early stage. But if its gotten too far, use copper medications like Seachem Cupermine.

Columnaris and Mouth Fungus

Columnaris or the mouth fungus, as the name suggests, forms in the mouth of a guppy fish. It can also form in the mid-section of their body with a big white splash.

The infected fish lose it’s appetite and have trouble swimming. The infection actually paralyzes the muscle weakening their abilities.

Columnaris is a highly contagious bacteria that usually affects female guppies. Having said that, the male guppies are also prone to the infection. If you don’t treat columnaris in time, it can wipe out the entire colony of fish in the tank.

What are the causes:

It might be considered a fungus, but columnaris is actually caused by bacteria. An overcrowded tank can be major cause in spreading the infection to other fishes.

How to treat Columnaris and Mouth Fungus:

The sooner you start the treatment, the better when it comes to curing columnaris. Use atibiotics like Formalin or Maracyn depending on the situation of the disease.

You can also use Potassium permanganate with a 30 minute bath to cure columnaris. However, make sure to use it carefully as it can burn your fish.

You can also cure columnaris by using aquarium salt. Add one teaspoon of salt per gallon of water everyday for at least three days. And do a 50% water change as well.

And make sure that your tank isn’t over crowded.

Popped Eyes

Popped eye might not be a fatal disease, however, if not treated on time, it might cause blinding in guppies (or any other fish).

What are the causes:

Popped eyes is a common disease among the guppy fishes. However, the most problematic thing about it is that there aren’t any particular phenomenon that causes popped eye.

There are several common causes of the popped eyes in guppies like internal parasite, bacterial infection, tuberculosis, dropsy, fungus, and poor quality water.

How to treat Popped Eyes:

The cure for popped eye is very hard to figure out. Since it is caused by a lot of things, until and unless you don’t know what caused it, any medication can be harmful.

Of course its a good idea to clean the water on a regular basis. But anything other than that is highly risky in this case.

Swim Bladder Disorder

Swim bladder is one of the internal organs of fishes. It helps them control their buoyancy and is filled with gas. The organ helps the fishes maintain it’s balance while swimming and staying put at current water depth.

But when the guppies are stressed, they develop swim bladder disorder. However, it is not as common in the guppies.

What are the causes:

The primary cause of the swim bladder disorder is high stress. When you move the guppies from shallow water to deep water, they are unable to control their swimming and keeping the balance. Thus, it stresses the guppies out.

It can also be caused by high ammonia in the water.

How to treat Swim Bladder Disorder:

The best remedy for swim bladder disorder is to maintain a high water quality. Regular partial water changes is very important to keep the disorder at bay.

Fish Tuberculosis

Tuberculosis in fish can cause in loss of appetite. And as it develops, the guppies will have hollow-belly and ulcer that affects their bodies around their anus. They also start getting discoloration as well as tail and fin rot.

And as the disease spread, the fish becomes inactive and die.

The highly contagious disease can spread pretty quickly if the infected fish isn’t removed from the tank immediately. Tuberculosis can also pass on to the offspring.

What are the causes:

Tuberculosis in fishes is caused by a bacteria named Mycobacterium.

How to treat Fish Tuberculosis:

Treating tuberculosis in a fish can be pretty hard as there aren’t many remedies available.

If the fishes shows signs of tuberculosis, quarantine the fish as soon as possible. You can then treat it with antibiotics like Isoniazid, Neomycin, or Kanamycin.

If the fish dies, remove it immediately from the tank. And if the quarantined fish shows no signs of improvement, its better to properly euthanize the fish so you avoid the spreading of the infection.

Bent Spine (Scoliosis)

Bent Spine

Bent spine, also known as crooked back or Scoliosis is a common disease in guppies. It usually affects younger guppies. Guppies with scoliosis are usually bullied as they are weaker and have trouble swimming properly.

What are the cause:

Usually, the main cause of bent spine is in-breeding in guppies or any livebearing fish. It is also a genetic disorder with a high chance for offsprings inheriting it from the mother.

How to treat Bent Spine:

There aren’t any remedies for scoliosis. The only thing you can do is take care of every little aspects of their lives. Since it is caused by environmental factors, try to make sure that the guppies are living in a healthy environment. And on top of it all, provide them </LINK>good food and healthy diet</LINK>.


To avoid any disease in guppies, the best thing to do is to keep their surroundings clean. Make sure you change the water on a regular basis. And also maintain the temperature of the tank at all times.

Clean the filter and the tank on a regular basis as well. Make sure your guppies get a healthy and balanced diet. And of course, keep a safe and healthy environment for guppies to grow and thrive.

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