Columnaris Betta Fish Treatment Guide

We never want to have our aquatic buddies get sick, but if it happens, we do need to be prepared. The best way to do that is to know everything we need to know about the ailment.

In this post, we will explore the common fish disease called columnaris in our columnaris Betta fish treatment guide.

columnaris betta fish disease


What is Columnaris? 

Also known as cotton wool disease and saddleback disease, columnaris is considered a symptom that results from an infection caused by the Gram-negative, rod-shaped, aerobic bacterium, Flavobacterium columnare.  It got its name because the bacteria are rod-shaped. It is also very, very small and only visible under a microscope.  

Although it is more prevalent in livebearing fish (such as guppies), Betta fish can still contract this disease under the right circumstances. It enters your Betta’s system through its mouth, gills, or open sores. 

This disease is highly contagious among tankmates and can be fatal if left untreated. 

What Causes a Columnaris Outbreak in a Tank? 

Interestingly enough (and a bit worrisome) is that columnaris are always present in aquarium water. However, healthy fish with strong immune systems can usually resist it.

Here are the common causes of a columnaris breakout in an aquarium. 

  1. Overstocking – if your tank has too many fish in it, then it can lead to “bioload.” This is when the filter cannot keep up with the fish waste and the water quality can turn poor. This polluted environment then becomes a breeding ground for all sorts of bacteria and fungi. 
  2. Stress – when a Betta fish becomes stressed, it reduces his immunity, which, in turn, leaves him open to disease. 
  3. Poor Tank Conditions – failing to perform regular tank maintenance, fluctuating temperatures, and pH levels can also promote columnaris growth. It will also stress out your Betta, leaving him with a lowered immunity. 
  4. Poor Diet – low-quality food will not promote good health in your Betta.
  5. Transferred From New Fish – new members of your aquarium community could have come into your tank harboring the columnaris bacteria. Once in your tank, it can spread very quickly to the other tankmates. 

Symptoms of Columnaris 

Because columnaris can be deadly, you will want to catch it quickly to have the best chance of curing your Betta. 

Here are the symptoms of columnaris;

  • Frayed or ragged fins
  • Bleached or pale-colored patched on the body of the fish (sometimes presenting as yellow or orange)
  • Patches will be flat (not bumpy or fluffy).
  • Split skin
  • Scales falling off
  • Long filaments on the body
  • Bright red patches (as the disease eats away at the fish, its muscles will be exposed as red patches)
  • A distinctive round patch behind the dorsal fin (may resemble a saddle – why it is referred to as “saddleback” disease)
  • White and swollen around the mouth (if the bacteria started as a mouth infection).
  • Bloody-looking gills
  • Rapid breathing 
  • Gasping at the surface of the water
  • Scratching on objects or substrate

Steps to Treating Columnaris 

Once you have identified your Betta’s illness as columnaris, you will want to begin treatment as soon as possible for the best chances of pulling him through it. 

Follow these steps closely, as incorrectly treating columnaris can also be deadly to your Betta. 

Step #1 – Quarantine Your Sick Fish

Anytime a fish is ill, it is best to remove him from the community and place him in a hospital/quarantine tank (if your Betta is alone in the tank, then you do not have to quarantine him.

Using a hospital tank is advantageous in many ways;

  • It helps prevent columnaris from spreading to the tankmates
  • A sick fish may be bullied by the healthy ones which lead to further stress on the ill one and the healthy fish
  • Smaller tanks are easier to dose (use less medication)
  • Healthy fish will not be exposed to medications they don’t need (which can be dangerous to their well-being)

Step #2 – Check the Water Quality

To successfully treat columnaris, your tank’s water conditions need to be pristine. The way to gauge your water quality is to use a test kit. 

Test for these parameters in your Betta tank;

  • pH – 6.5 to 8
  • Ammonia – under 0.5 ppm (parts per million)
  • Nitrite – under 0.5 ppm
  • Nitrate – under 20 ppm
  • KH – above 80 ppm
  • GH – 70 – 300 ppm

Getting your tank’s water quality to acceptable levels will not only affect how your fish reacts to the medications but also, how the medications work inside the environment. 

Step #3 – Lower the Heat

Columnaris loves the heat, so to help destroy this bacterium, lower the heat in your Betta tank. Ideally, your Betta tank should not be above 75 degrees Fahrenheit to successfully treat saddleback disease. 

However, do not rapidly reduce the heat. Fish, especially those already compromised, are sensitive to temperature changes. To safely lower the heat, turn the thermostat down by two degrees every hour until you reach 75 degrees. 

Use a good aquarium thermometer to gauge the temperature. 

Step #4 – Begin Treatment

Before you begin dosing your aquarium, you will want to remove the activated carbon from your filter. This will deactivate the medications. 

Experts recommend using a combination of nitrofurazone (name brand Furan-2) and kanamycin (KanaPlex). They work best when used in tandem, as opposed to using just one or the other.

Follow the instructions on each package for specific dosing according to tank size.

Here is the recommended schedule;

Day 1 – Furan-2 and KanaPlex

Day 2 – Furan-2

Day 3 – Do a 25% water change, then add a dose of Furan-2 and a dose of KanaPlex

Day 4 – Furan-2

Day 5 – Perform a 25% water change, then add a dose of Furan-2 and a dose of KanaPlex

Assess your Betta. Does he still have symptoms of columnaris? You may need to repeat the process for a second round of medication.

Columnaris Prevention Tactics 

If columnaris is always present in an aquarium, then why don’t all fish contract the illness?

We already know that stress is the leading cause of illness in fish. Stress can be brought on by many different situations like overcrowding, and a polluted environment. 

So, if you keep stress out of your tank, your Betta has less chance of getting columnaris. 

However, providing your Betta with a relaxing, stress-free habitat isn’t the only columnaris prevention tactic.

You will also want to:

  • Quarantine new fish before adding them to your tank.
  • Follow the 1-inch of fish per gallon of water rule (in other words, DO NOT overcrowd your community)
  • Only house compatible species with your Betta
  • Aim for the optimal water parameters by doing regular tests and making the adjustments when necessary
  • Clean and maintain your tank regularly
  • Feed your Betta a quality diet and do not overfeed him
  • If your tank has hard water issues, reduce the GH – it is more difficult for columnaris to flourish in softer water. 

Final Thoughts on Columnaris Betta Fish Treatment Guide

Columnaris is always present in our aquarium habitats but that doesn’t mean our Betta has to contract it. Be mindful of keeping his aquarium pristine with regular water changes and maintenance. Do not overcrowd the aquarium or overfeed your aquatic pals and always quarantine new tank mates before adding them to an established habitat.

If you do suspect your Betta is sick, check for the tell-tale signs of columnaris, then treat him accordingly. Catching this ailment in the beginning stages will give your Betta the best chance of beating it.