How to Recognize and Treat Columnaris Betta Fish Disease

Columnaris is a kind of bacterial infection we frequently see in betta fish.

Despite its prevalence, we can prevent Columnaris with lots of care and attention.

If your betta has been affected by this illness, fear not! There are plenty of treatments to fall back on.

columnaris in betta fish

What Is Columnaris?

Columnaris is a bacterial infection. The bacteria responsible is flavobacterium columnare, where it gets its title.

You may also hear Columnaris by one of these names:

  • Cotton wool disease
  • Saddleback disease
  • Guppy disease
  • Cotton mouth disease

Many of these alternative names describe the characteristics of the disease. The name Columnaris comes from the bacteria itself.

Is Columnaris Contagious?

Columnaris is a contagious disease.

Once the bacteria is in your aquarium, all the fish inside are at risk of contracting the disease.

To prevent the further spread of the illness, you need to quarantine sick fish.

Furthermore, your tank needs to be cleaned out thoroughly.

We normally don’t recommend moving your fish from tank to tank. But in this case, it needs to happen.

Get a separate tank ready and move your fish there while you clean their home.

Some people use a vinegar solution to rid the tank of bacteria. Other people use bleach.

Bleach is a bit of a scary substance to most aquarists. But there are safe ways to clean an aquarium using bleach as your cleaning agent.

How Does Columnaris Affect Betta Fish?

Columnaris often affect your betta’s fins and tail before moving to the rest of the body.

Over time, symptoms get worse and may impact your betta’s ability to breathe properly.

This is a complete list of possible signs of Columnaris:

  • Frayed/ragged fins
  • White/gray patches
  • Redness/inflammation
  • Excess mucus
  • Discoloration
  • Abnormal behavior (i.e., rubbing, gasping, etc.)
  • Decreased appetite
  • Skin loss
  • Swollen/pale lips

Some of these symptoms are very common among other betta diseases.

For example, fin rot causes similar fin damage to Columnaris. They both may start with your betta’s fins or tail being injured.

But fin rot does not tend to cause the same extent of white sores and mucus production.

It is worth noting how fin rot is sometimes caused by infections such as Columnaris.

Late Stage Columnaris

Mucus production is how your betta’s body naturally attempts to fend off the disease.

The Columnaris is in your betta’s skin, so they may rub up against surfaces in the tank.

By rubbing and producing a lot of mucus, your betta hopes to get the Columnaris “off” so to speak.

These are natural ways your betta may fight the condition. Yet you still need to give them commercial treatment.

If you leave things to progress further, gill damage becomes a serious possibility.

Damaged gills will start to turn brown and may appear to rot away. 

At this point, your betta struggles to get much-needed oxygen.

You might notice they start hanging out near the tank’s surface or appear to be gasping for air.

This is because they are unable to get adequate oxygen through their gills. So they need to get it another way.

What Causes The Columnaris Betta Disease?

For Columnaris to infect your betta, it needs two things:

  1. The bacteria must develop in or be introduced to the tank.
  2. The betta must be exposed or vulnerable in some way.

How Does Bacteria Get into the Tank?

Poor water conditions and a heavy bio-load encourage dangerous bacterial growth.

Bad water quality often starts with waste build-up and inconsistent cleaning.

Bacterial growth is way more common in dirty tanks than in clean ones.

Tanks lacking oxygen are also more likely to see Columnaris outbreaks.

Good chemical filtration is vital to keeping your betta in a safe aquarium environment.

Most species of bacteria struggle to survive in a clean tank. Good water maintenance makes a huge difference to your betta’s health.

Outside of maintaining good water conditions, you must use a proper quarantine tank for any new fish!

This is an additional step a lot of people overlook.

But following proper quarantine procedures is an easy way to avoid disease outbreaks.

This is also why cleaning up all contaminated equipment from old tanks is so important.

If aquarium equipment is used on a sick fish and not sanitized properly, it can spread bacteria.

What Makes Your Betta More Vulnerable to Infection?

First and foremost, sick and injured betta fish are at a high risk of developing infections like Columnaris.

Open wounds and lesions from injury or parasites make it easy for flavobacterium columnare to infect your beloved betta.

The betta body is particularly vulnerable to torn fins or tails because their tails tend to be very long!

To avoid injury, use soft plants and decor in your tank.

Stress and shock are two more ways your betta may become vulnerable.

Betta fish don’t usually get a lot of tank mates. But if you house them with a friend, make sure they live with very healthy tank mates.

They should never live with larger fish or potential predators, either.

Putting a betta in a community tank or otherwise crowded environment is a recipe for serious stress.

A high-stress level is visible in betta fish as it causes their colors to dull and may cause them to develop stress stripes.

Shock tends to come from environmental changes. Sudden temperature spikes or dramatic changes in pH may shock your betta.

The Columnaris bacteria is a relatively common freshwater bacteria. Your betta may be infected even if you do everything right.

This is why we urge you to focus on diagnosis and treatment.

Getting a Columnaris Diagnosis

Veterinarians diagnose Columnaris for the most part.

An experienced fishkeeper can diagnose if they know what to look for, though.

You want to be completely certain this is the bacteria flavobacterium columnare. The best way is to get a sample of the infected area.

How to Treat Columnaris in Betta Fish

The good news is, your betta has an excellent chance of recovery! 

Hospital Tank (Sick Fish Quarantine)

There are several different treatment options. But each treatment procedure starts with a hospital tank.

Move the infected betta to a separate hospital tank before administering any kind of treatment.

The water in this tank must be clean and meet the ideal betta water parameters. It needs a filter and some plant life as well.

You want to encourage low stress levels while keeping the tank sterile.

Meet good oxygen requirements here too! You may need to get an air stone or other kind of aerator to help raise the oxygen level. 

Do not use equipment from the old tank. All contaminated equipment needs to be sanitized before you reuse it.

Your betta’s old tank will need a deep clean before they can return to it.

Types of Treatment

You get to pick from the following treatment options in the hospital aquarium.

  • Antibiotics
  • Medicated food
  • Hydrogen peroxide
  • Copper sulfate

We recommend you use Columnaris medications specifically for this type of bacteria.

Using the correct medication raises your betta’s chance of survival. It also helps them heal faster.

Antibiotic and recovery treatments like Melafix and Bettafix help your fish fight the disease and heal from fin damage.

It is imperative to use targeted treatments like this if your betta’s Columnaris infection has progressed a lot.

If you’re only seeing small amounts of fin damage, medicated food might be enough to help.

For example, here is one immune-boosting food available on Amazon.

This is not so much a direct treatment for Cotton Wool as it is an immune system supporter.

Again, antibiotic treatment is the most effective, and we urge you to use it on your betta.

Other alternatives include the external use of hydrogen peroxide and copper sulfate. These treatments are much riskier.

Both substances are toxic to betta fish if they aren’t used correctly. Exercise caution if you use them, and be sure to consult an expert.

Tips for Columnaris Prevention

Poor diet weakens your betta significantly.

Feed them lots of protein and give them food with immune-boosting vitamins.

Water maintenance is arguably the most critical factor in keeping your fish healthy.

This means keeping ammonia and waste levels as low as possible, for one thing.

Perform weekly water changes of about 25% to keep waste from building up. Use a gravel vacuum to clean the tank more deeply as needed.

Use an aerator and a good filter to meet oxygen requirements in the tank water.

Remember, sudden temperature or pH changes are also hard on your betta. You need to keep aquarium conditions as consistent and stable as possible.

The appearance of the environment is somewhat important too.

Your betta needs lots of plants and decor to feel safe and comfortable. Just ensure you only add soft plants and never use sharp decor.

Sharp and hard edges may cause injuries to your betta’s fins or tail. This makes them more susceptible to bacterial infections.

Preventative Care

Some betta owners use aquarium salt semi-regularly even when there are no presenting problems.

This is understandable as aquarium salt is a go-to for many betta fish keepers. But it comes with risks all its own.

Read our article on how to safely use aquarium salt if you’d like to be more familiar with it.

Otherwise, some water conditioners protect your betta from bacterial and fungal infections.

This is one such conditioner by API, which is extremely well-liked among betta fish keepers.

But there are a ton of preventative treatments out there.

FAQ on Columnaris in Betta Fish

How is Columnaris different from other betta diseases?

Lots of betta diseases have environmental causes. But not all of them are caused by bacteria like Columnaris. Dropsy, Swim Bladder Disease, and some others are a result of digestive issues and poor nutrition.

Columnaris is a bacterial infection. Thus treatment is different from SBD and other illnesses too. Columnaris is commonly treated with antibiotics or medicated food.

Meanwhile, SBD, for example, is treated with Epsom salt baths.

How long before a betta shows symptoms of Columnaris?

Cottony sores tend to develop over just a day or two. From this point, the disease progresses depending on the health of your fish.

A strong and well-fed betta may take several days to see gill damage. Meanwhile, a betta who was already sick or had a poor immune system could die in another couple of days.

This is why it’s so essential to start Columnaris treatment as soon as you know what you’re dealing with.

Is Columnaris a fatal disease in betta fish?

Columnaris is fatal to betta fish if left untreated. When you catch it early, it’s highly treatable. But over time, your betta’s gills are damaged, their skin starts coming off, and they struggle to breathe.

At this point, the disease has progressed very far and could turn fatal. Start with the proper treatment when you see symptoms like ragged fins and white sores.

How does diet affect Columnaris?

Unlike SBD or bloat, diet is not a significant player in Cotton Wool Disease. A healthy diet can certainly help prevent your betta from contracting Cotton Wool.

Eating nutritious foods is also an excellent way for your betta to keep up their strength. This helps them fight the disease once they have it.

The Gravity of Columnaris in Betta Fish

Clean water conditions and low betta stress discourage bacterial infections like Columnaris.

Once they are infected, you see symptoms like white sores, lesions, and fin or gill damage. You must act fast once your betta is infected.

Their chance of survival is high but drops if you leave them untreated.

Not sure it’s Columnaris? Read up on other common betta diseases.

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Jacinta was raised on a dairy farm in Vermont where they worked extensively with cows, chickens, pigs, goats, and other animals. They have a background in writing both creatively and professionally.

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