What is Columnaris?
Columnaris disease is caused by Flexibacter Columnaris bacteria. It has many nick names including cotton wool disease, cotton mouth, flex or mouth fungus. It is a disease that is often mistaken for a fungal infection due to lesions that have a mold-like appearance. Infection occurs in fish that have been stressed out by unhealthy water conditions, poor diet, or other stress inducing activity such as bullying and being carelessly transported. Columnaris can be an internal or external infection so there can be a wide variety of symptoms associated in different cases.
What are the symptoms of Columnaris?
stringy white growths
cottony patches (white, grey, or yellowish brown)
mouth looks “moldy” and starts to decay
fins will seem to erode which could possibly be a case of fin rot occurring due to the stress of flex
ulcers or lesions (advanced stage)
if gills are infected:
change in color(gills turn brown)
gasping at surface
rapid gill movement
What to do before medicating…
Before you do anything, if your fish is in a tank with others, you need to quarantine the affected fish in a separate tank. This will help prevent the whole tank from becoming infected.
Once your ill fish has been removed from the others follow these steps on the original tank for further infection prevention:
1. Perform a 25% water change making sure to siphon the gravel of organic materials that can be a food source for the bacteria. Be sure to remove all decorations from the aquarium. You can either soak the ornaments in a hot water and bleach solution, or let them sit out until dry. The lack of hydration will kill any living organisms on your tank supplies.
2. When you add water back into the tank add aquarium salt. This will aid in healing by encouraging the production of mucus and reducing the number of pathogens. Bacteria and parasites do not have the organs necessary tolerate the change in sodium levels.
NOTE: If you have Corydoras or “Corys” in your tank refrain from using aquarium salt. They do not tolerate brackish water and could fall ill.
Medicating the affected fish…
Now to medicate. Columnaris is a negative-gram bacteria. You will need to treat both the tank and the “hospital” tank with an antibiotic. Be sure the medication you choose treats negative-gram rather than positive. A few examples of effective medications include Tetracycline and Kanacyn (Kanamycin sulfate).
Copper sulfate can also be added. It is used as an all-in-one treatment because it can cure infections caused by fungus,
bacteria, parasites and even kills algae. A word of warning, however, it is often overdosed so be absolutely careful when measuring. Also, when used to kill algae, it gets re-released into the water once the algae dies.
It can be very difficult for a betta or any fish to recover from this disease. So be sure to treat Columnaris as soon as you can diagnose it.