Do Your Guppies Have Columnaris? (Diagnosis and Prevention)

Do Your Guppies Have Columnaris? There really is a lot of time and effort that goes into your guppies. It all begins with your providing the right living environment for them right on through to keeping them in prime health.

So, as a fish lover you must know various diseases and their symptoms and track them properly.

You have to always be on the alert that none of them are getting sick, as one sick guppy could wipe out your entire tank population.

Some of the common guppy diseases are easier to detect than others, just as some are easier to treat.

There are 3 things that you need to focus on when it comes to guppy healthcare.

This is the diagnosis, treatment, and prevention.


The first thing you have to do is really know your guppies as they appear in their healthy state. This way you are going to notice any changes in them much faster.

Also, be aware of what the most common diseases and illnesses that could afflict your guppies and what their related symptoms are.


Columnaris (also known as cottonmouth) is a visible symptom of the fish disease that results from an infection caused by Flavobacterium columnare an Aerobic, Gram-negative, rod-shaped bacterium.

people have often mistaken it with a regular fungal infection. But Eventually, This disease is far more lethal and contagious than fungus and the outcome are usually fatal or death.

What causes Flavobacterium?

(F. columnare) or Flavobacterium is a disease causative agent of columnaris.

This bacterium affects all types of fishes including wild freshwater fish, fish that is imported or cultured.

Fish Columnaris Vs Fish Fungus Saprolegnia

Going over the fish diseases of white patches on fish and fungus, such as mouth fungus.

How to identify white patches splotches on a fish? Is it bacterial Columnaris or Funus/mold Saprolegnia?

Treatment of the two is different, so we know to identify it correctly. Betta fish fungus cure and fish has white spots.

What fish fungus medicine do you use? The difference between these two fish illnesses.

Major tropical fish disease and knowing the difference will make all the difference in treatment.

Treatment for all fish, including popular goldfish fungus cure. White patches on goldfish. What to do for fuzz on fish, which is actually molded. Fungi and fish.

White growth on fish. Columnaris is also going to be on the living tissue of fish, whereas Saprolegnia is going to be on dying or dead tissue.

In both cases Prevention is key! Mineralization plays a huge role in not contracting Columnaris, based on our experience and in-depth research.

Treating Columnaris Disease in Aquarium Fish

This is a common illness to strike guppies and it is bacterial oriented.

You may start to see white markings or patches appearing on the guppy these could be on the body or just starting around the mouth area. They almost look like white threads.

As this often begins around the mouth area some owners get mixed up with thinking that it is mouth fungus which is another type of disease.

If the disease is left unattended or advances quickly you will see that the fins of the affected guppy are beginning to deteriorate.

Then sores begin to show on the body. As the disease advances the guppy will not be able to spread his fins and will hold them close to his body.

Various strains of Columnaris.

Strain #1:

Usually, no noticeable symptoms but has been known to attack and destroy the total aquarium stock within 24 hours.

Strain #2:

Very similar to strain #1 but the death of the fish is not so acute but spans over several weeks.

Strains #3 and #4:

These are the more common types and not as deadly as the others.

In strains #1 and #2, it seems more prevalent in warmer temperatures,

while in stains #3 and #5 it is more common in cooler temperatures.

Understanding the Guppy Strains

Once you have a few guppy fish for a while you will want to expand and get into breeding.

When you make this decision you then have to really start looking at the different types of guppy strains.

There are many to choose from and who you choose to buy your breeding stock from is going to be important.

You will probably find that if you are using your local fish store to purchase your fish from that the main strains you will find there is the fantail or at the Deltatail.

You will notice the characteristics of these guppies in that they have flowing tails and dorsal fins which are quite wide and they are usually the same color or have the same pattern.

How many strains does a guppy have?

The guppy, Poecilia reticulata, has about 30 strains with different fin shapes and color patterns, They are reared in guppy farms that practice monoculture.

If you reach out to serious guppy breeders who are selling breeding stock you will find that,

They have a selection of sword tail or linear tail guppies, again in many different variations.

You may not see these particular strains in your local store because they are not as brightly colored or don’t have as many colors as the fantails and the Deltatails do.

In most of the strains, it’s the male that is the most colorful and has the larger fins.

however, In good show stock, you can find females have a good amount of color in their dorsals and tails.

In most cases, the females in any strain don’t have very much body color.

Some guppies are referred to as unicolor where their body tail and dorsal fins are all same color.

For Further Reading: Guppy Fungus (Types, Causes, and Remedy)

Additionally, you will also come across some guppies that have unique looks to them like the Tequila Sunrise.

In this particular strain, you usually get male-only, as the breeders like to encapsulate the market to prevent females out for breeding.

Another type of strain is the Moscow guppies which are solid in color and large in size.

They are sturdy fish and are most noted because of their large flowing fins you will not come across these too often as they have not really hit the open market of the general fish stores as yet.

It can be difficult when purchasing breeders from other locations.

because what may be named as a strain in your area may have a different name for the same strain in another area.

When you are showing your guppy there are going to be criteria that your guppy must meet in order to enter and perhaps win in their category.

For example, if you are going into the swordtail categories then you have to be aware that the swordtail does come in a single or double swordtail.

If you have one that has a single tail then enter them into single swordtail class and likewise for the double swordtail.

The Delta tail guppy has a tail that looks very much like a triangle.

You will definitely want to give some planning and thought to which breed you want to concentrate on especially if you are going to enter into the show world of guppies.


How do you treat columnaris in guppies?

How effective your treatment is going to be will depend on how quickly you can detect it.

Usually, if you can catch it in its early stages then an anti-bacterial medication will work.

In the Advance stages when the disease starts invading the internal organs of the guppy,

It needs drastic treatment and administration in the form of antibiotics.

How do you treat Flavobacterium columnare?

Flavobacterium columnare is Aerobic and Gram-negative, which means we can treat the infected fish with the following:

A combination of antibiotics such as nitrofurazone + kanamycin

Administered together in specified proportion under vets supervision.

Can humans get columnaris? The simple answer is No, Humans are not at risk for columnaris.

To keep the water clean we need to pay extra attention most of the time.

Terramycin has proven to be quite effective both as a bath, and when used to treat foods for internal infections.

We can also add salt to water in proportion (1 to 3 teaspoons per gallon of water).

This reduces osmotic stress from the damage on fish’s epithelium caused by the bacteria.


How do you avoid columnaris in guppies?

Considering, this is bacterial in nature, make sure your tank is as clean as possible.

Often it is poor water quality that allows for Columnaris problems.

Moreover, some fish when introduced to a new aquarium suffer shock which in turn makes them susceptible to Columnaris.

Make sure when you are seeking out treatment for your fish with Columnaris that you rely on the advice of a professional that can provide you with the right medications.

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