Guppy Dropsy (Causes, Treatments, Prevention, Symptoms)

Guppy dropsy is extremely serious. In fact, it’s one of the most serious things that can happen to your guppy. In this article, you’re going to find out the best ways to treat dropsy, what causes it, the symptoms, and most importantly, how to prevent it from happening in the first place!

So keep reading to find out everything there is to know about dropsy in guppies!

What Causes Dropsy In Guppies?

First of all, you may be wondering what causes dropsy in guppies. Well, while it’s generally a bacteria that infects your guppy and kills them. This isn’t the true cause. In fact, the bacteria that causes dropsy in guppies is present in the tank at all times.

It’s only when a guppy’s immune system becomes compromised that they’ll suffer from dropsy. And there are actually a lot of things that can weaken your guppies’ immune system. Some of the most common causes include the following.

Poor Water Quality

The main cause of dropsy in your guppies will probably be poor water quality of some sort. If you don’t vacuum your gravel, change the water, remove old food and decaying plant matter, or have a filter, then the chances are, the quality of the water is going to become poor.

Not only this, but, ammonia is also going to build up in the tank, which could result in an ammonia spike which can become fatal extremely quickly as well.

Poor Nutrition

Another common cause of dropsy is often poor nutrition. If your guppy isn’t getting the food they need, then obviously they’re going to suffer. On top of this, they’re immune system will also weaken. Opening them up to dropsy and other diseases.


Dropsy can also occur when your guppy has sustained an injury. This can happen at any time. However, when you’re transporting them from your home to your tank can often be the most common time.

As well as this, they could also be injured by other fish who are bullying them as well as decorations in your tank which have damaged them.

Other Illnesses

If your guppy is already suffering from an illness, then it’s going to increase the chance of them suffering from dropsy as well. Once again, this is due to the fact that their immune system has been weakened.

A Sudden Change In Water Temperature

Lastly, a sudden drop or increase in water temperature can also increase the chance that your guppy is going to suffer from dropsy too. This is going to wreak havoc on their body. And if you don’t act quickly it can also kill them, thanks to something called temperature shock.

What Are The Symptoms Of Dropsy In Guppies?

To know whether your guppy is suffering from dropsy, or whether it’s something else (such as constipation or swim bladder disease), then you’ll need to know the symptoms.

Here are some of the most likely symptoms you’ll notice when your guppy is suffering from dropsy.

Pinecone Scales

One of the tell-tale signs of dropsy is pinecone scales. In fact, when you notice this you can pretty much guarantee, that’s what your guppy is suffering from.

The reason the scales pinecone is because the body has swelled so much, that they can no longer stick to their sides.

At this stage of dropsy, it’s highly unlikely that you’re going to be able to save your guppy, and euthanasia may be the best decision.

A Swollen Stomach

Another sign of dropsy in your guppy is a bloated, swollen or distended belly. Once again, this is because the infection and damage in your guppy’s body has caused it to swell massively.

However, just be careful you’re not mistaking it with swim bladder disease or constipation which could also cause this on a less severe scale.

A Curved Spine

As well as this, sometimes your guppies spine will begin to curve too. This is because the pressure inside their body is literally bending their spine. When the spine swells, though, it should be horizontal and not vertical. If it’s vertical then they may be suffering from tuberculosis.

(There can be many different reasons that your guppies spine is bent, however, so you should check this article out to figure it out!)

As well as the three main symptoms, you may also notice the following:

  • A lack of appetite.
  • They avoid other fish.
  • They hide in one part of the tank.
  • Their fins are clamped by their side (this is often due to pain caused by the swelling.)
  • Their gills have lost color.
  • And bulging red eyes and anus, which is caused by fluid retention.

While your guppy may not have all the symptoms listed above, if you do notice three of the main ones, then it’s most likely going to be dropsy.

How Do You Treat Guppy Dropsy?

If your guppy has dropsy, then you can still try to treat it. However, it’s important to know that if your guppy is suffering from dropsy, then there is a strong possibility that they aren’t going to survive.

With that being said, here are the different ways you can treat dropsy in guppies.


The first thing you should do is remove your guppy from their tank and quarantine them on their own. Doing this is going to help alleviate their stress, and also to help you treat them more effectively.

You also reduce the risk of infecting other fish in your tank, and lastly, you’ll be able to treat your sick guppy without having to worry about dosing other fish in your tank too.

When you’re setting up a quarantine tank, you should take some of the biological filter media from your first tank, as well as some of the water. This way good bacteria will be moved into your quarantine tank, and your guppy won’t have to acclimate to new water parameters.

Aquarium Salt Treatment

Once you’ve quarantined your guppy, the next treatment you should try is salt treatment. You generally want to use 1 teaspoon of aquarium salt for every gallon of water in your tank.

However, don’t just place the salt straight into your tank. Instead, you should take out a small amount of tank water, and dissolve the aquarium salt into the water.

Once you’ve done this you can then add it to your quarantine tank. For the exact dosages and how long you need to use it, you should check the instructions. This will give you a good guide on what to do.

As well as this, make sure that you never dose the same water twice. You’ll need to perform a 100% water change every time you dose the tank so you don’t make the water too salty.

Lastly, make sure you’re using aquarium salt and not any other kind of salt. Aquarium salt is made for treating fish when they’re sick, whereas other salt isn’t.

Feed Them A High Quality Diet

While you’re treating your guppy with aquarium salt, simultaneously, you should also be feeding them a high quality diet.

A high quality flake food is going to be the best choice, however, this should also be supplemented with some live food and blanched vegetables as well.

Make sure you’re removing any food that hasn’t been eaten to slow down the build up of ammonia in your tank. This will help to keep your guppies immune system strong.

If you’re not sure what type of food to use then I highly recommend TetraMin Tropical Flakes. However, any of the food on this list will be a great choice for your guppy.


Lastly, you may also wish to try medication as well. This is normally the quickest and most effective method for treating your guppy. However, if you get the dosages wrong it can go wrong a lot quicker as well.

I’d recommend using a product such as API Melafix, however, you should consult a veterinarian before trying anything.

To use API Melafix, you should check the instructions on the outside of the bottle. They’ll tell you exactly what you need to do to keep your guppy healthy and happy.

How Do You Prevent Dropsy In Guppies?

Fortunately, dropsy is preventable when you take care of your guppies and the tank that they’re in. If you follow the advice below, then you’re going to drastically reduce the chance of your guppies suffering from dropsy.

Change The Water Often

One of the most common reasons that your guppies will become sick is when the water is dirty. While a filter can keep it clean for a long period of time, you’re always going to need to change the water.

The amount of water you’ll need to change will depend on the size of the tank as well as how many fish you have in it. The smaller and more stocked your tank is, the more it will need it’s water changed.

Use A Filter And Heater

A filter and heater is also going to keep the water parameters in your tank as close to perfect as possible.

Without a filter, your tank will become dirtier much quicker, increasing the buildup of ammonia and bacteria in the tank.

And without a heater, it will only take one massive temperature drop to cause serious damage to your guppies.

So as you can see, both are tremendously important for keeping your guppies alive.

(Here’s a more in-depth explanation as to why you need a heater and filter.)

Clean The Tank

As well as using a filter, and changing the water regularly, you should also be cleaning your tank regularly as well. This means vacuuming the gravel to remove any build up of a grime, as well as scrubbing the walls and cleaning the filter.

Doing all of this will remove any parasites, bacteria and fungus that could contribute to your guppy suffering from dropsy.

Don’t Overcrowd Your Tank

The more overcrowded your tank is, the higher the bioload will be. If your filter can’t handle an increased bioload then the ammonia and bacteria will rise in it rapidly.

However, not only this but the more fish there are, the more likely it is for aggression to occur. All fish, no matter how peaceful they are, need their own space.

And if they don’t have this then they may begin to act in an aggressive manner. This could result in fighting which in turn could lead to dropsy.

(Find out how many guppies you should keep in a 5 gallon, 10 gallon and 20 gallon tank.)

Feed Them A Variety Of Food

You should make sure that your guppies are getting a varied diet. They’re omnivores, so they’ll need a mix of both plant and meat. However, tropical fish flakes on their own won’t be enough.

As well as feeding them tropical fish flakes you should also feed them live food such as daphnia, brine shrimp, and mosquito larvae. Vegetable wise, zucchini, lettuce, and peas all make a great choice, as long as they’re blanched first.

Feed Them High Quality Food

As well as feeding them variety of food, you should also make sure that you’re feeding your guppies high quality food as well. If you buy low quality food, then it’s going to have a lot more fillers in it.

These fillers are going to provide no nutritional value for your guppies, and in fact, could harm them.

(Here are some of the best foods you can feed your guppy as well as what their diet should look like.)

Don’t Overfeed Them

Overfeeding your guppies can often result in constipation and swim bladder disease. While these illnesses on their own are normally curable, they do weaken the immune system, opening it up for dropsy to strike.

When you’re feeding your guppies, you shouldn’t feed them anymore than they can eat in two minutes.

Don’t Add Aggressive Tank Mates

Lastly, make sure you’re not adding any aggressive tank mates into the tank. Obviously they’re going to bully guppies, which could stress them out or even cause damage to them.

In both cases, the chances of suffering from dropsy are going to increase.

(Some great tank mates for guppies include cherry shrimp, ghost shrimp, neon tetras, and even goldfish!)

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As you can see, dropsy is definitely something you don’t want your guppies to suffer from. As the prognosis is never good. However, with the right care, it is possible to bring your guppy back from the brink.

But the better option is to prevent your guppy from getting dropsy in the first place! So if you follow the advice above, you’re going to keep your guppies alive for a long time!

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