FLEXIBACTER- COLUMNARIS & FUNGUS (Saprolegnia):
|Sections Include: Overview & Complete Article/e-book Download|
* Identification of Columnaris (AKA Saddleback Disease & Cotton Wool Disease)
* Treatment of Columnaris
* More about Columnaris including Prevention/Water Quality
• FUNGUS/ SAPROLEGNIA|
* Saprolegnia (Fungus, mold)
* Lifecycle of the asexual Spores
By Carl Strohmeyer-PAMR 35+ years experience
American Aquarium Products:
Frequently Asked Questions
The fish in the lower right corner of the picture is displaying Saprolegnia while the rest are displaying Flexibacteria-Columnaris
Columnaris along with Saprolegnia in particular (Saprolegnia is often confused with Fungus) are two of the most misunderstood and often mistreated aquariums diseases, even Wikipedia has marginal information about these pathogens and their CORRECT treatment and prevention (as of my last reading).
Prevention is the key with both of these unrelated but similar symptom potential fish pathogens.
Please read both sections/articles in full for a better understanding of these common pathogens.
With Columnaris, it is important to learn the effect stress has in outbreaks as well as the importance positive mineral ions and the role these cations play in adhesion of Columnaris by reducing surface potential and repulsive forces.
See the Minerals/Redox Section of Columnaris prevention for a further explanation.
For Saprolegnia in particular, understanding the role of decaying organics, the lifecycle of Saprolegnia zoospores, and even pH play in prevention and treatment of the often very misunderstood Saprolegnia mold/fungi.
As well, after reading both sections, hopefully the reader will understand how the success of treatment of Saprolegnia, as in the disease, Aeromonas is often improved considerably by improving water quality.
Further Reference for Aeromonas:
Treatment, Identification, and Prevention of Aeromonas, Septicemia, Furunculosis, Vibrio
While success in "beating back" Columnaris is more aided (besides treatment) by removing stressors, such as a bullying fish or lack of electrolytes.
Also the progression of Columnaris is often simply aided by weak genetics (a VERY common cause with Bettas) which unfortunately there is little that can be done here other than culling weak fish, which sadly in many instances should be done to stop the spread/progression.
This is also where I find incorrect confusion between Saprolegnia and Columnaris since both look outwardly similar; persons and websites often state that they aided the cure of Columnaris by cleaning a dirty aquarium. This indicates that the fish more likely had Saprolegnia (or even Aeromonas) as you will see from reading the article in full.
Columnaris (often referred to in the past as "cotton wool disease" or "cotton mouth disease") is a warm water, gram negative strictly aerobic and nonhalophilic (meaning they do not live in saltwater conditions) bacterium often appears like a fungus (or more correctly; Saprolegnia) however it is not a fungus, although many treatments for fungus are effective for mild cases of Columnaris (Flexibacteria).
This is why the often recommended Erythromycin is a strange choice of treatment as it is rarely effective for either Fungus of Columnaris.
The picture above left is of fingerling Rainbow Trout displaying a characteristic white saddleback lesion caused by Columnaris bacterium & of a Rift Lake (Malawi) Cichlid displaying classic Columnaris symptoms after stress and injury often caused by an over-crowded cichlid tank
However do not confuse Columnaris with the spores of Saprolegnia the cotton wool ball with hair like growth structures seen on damaged fish. Without a microscope, Columnaris can look like Saprolegnia and is often treated as fungus, sometimes with poor results.
The best way to tell with the naked eye (using a magnifying glass) is the hair like growth structures of Saprolegnia/Fungus.
WITH a microscope, scrapings from a columnaris lesion then placed under a microscope will reveal long, thin, rod shaped motile bacteria. The bacterial clumps form microscopic columns or dome shaped masses, hence the name columnaris.
Columnaris has similarities to Aeromonas bacterial infections in that both are opportunistic (both generally present in some location of an aquarium), however since Aeromonas is a facultative bacterium & often anaerobic, it is more prevalent in a tank with high amounts of pollution, DOC and especially poor circulation.
While Columnaris being only aerobic (preferring high oxygen environments) can occur in tanks with good filtration/circulation, however it is common in a tank with poor Redox/mineralization, overcrowding, high temperatures, and stress (such as an aggressive fish tank where many inhabitants are constantly bullying others).
As well weak genetics from in-bred fish (as with many Guppies and Bettas) or fish such as "feeder" or "carnival" goldfish that are often permanently damaged for early life crowding are also often at risk for Columnaris infections.
Unfortunately the above point is missed by many who often cite dirty, stagnant, or otherwise poor water conditions as cause of Columnaris, but since Columnaris is aerobic, it simply cannot thrive in poor water conditions that are low in oxygen as can Aeromonas or Saprolegnia.
This is NOT to say that sudden shifts in parameters such as spikes in ammonia (assuming an aerobic environment), can will not trigger Columnaris, as this too is a stressor that can allow for an opportunistic Columnaris infection.
HOWEVER, as I have noted many times in my years in aquarium maintenance and "sick fish" service calls; dirty, foul, under filtered, low oxygen environments, RARELY trigger Columnaris infections.
Adding aeration without correcting mineralization problems based on false assumptions about Columnaris while ignoring ESSENTIAL mineral ions (Calcium in particular, but sodium chloride too) will only further force an out of balance Redox and not help with a cure of a true Columnaris infection!!
In lieu of often unavailable scientific microscopic identification, the above point is often noteworthy in identifying aerobic Columnaris from often anaerobic Aeromonas or the Mold Saprolegnia (generally referred to as "Fish Fungus").
Please read further for a better understanding of this bacterial disease as well as treatment and prevention (there is also a section about Fungus/ Saprolegnia as well)
The obvious first step is lowering stressors and improving water quality as outlined in these sections:
This also includes lowering water temperature to 75F (24C).
Failure to follow step one and just treating with medications is akin to asking someone for burn relief medications while still standing in a fire!
Additional salt is helpful at a dose of 1 tablespoon per 5 gallons OR HIGHER.
In fact a study at the Alabama Agricultural Experimental Station, Auburn University has shown increasing salt concentrations used with Channel catfish (along with heat reduction to 75 F) can treat Columnaris (Flexibacter) infections. This study flies in the face of anecdotal advice about not using salt with catfish.
You can see from the diagram that the best results were achieved at a dose of 3000 milligrams per liter; based on the weight of salt this converts .67 teaspoons per liter or 2.54 teaspoons per gallon. This is Much more salt than many aquarists commonly believe a Catfish can tolerate.
Please keep in mind that this amount of salt is NOT meant for long term use, rather just the duration of time it takes to reach a cure for the Columnaris infection.
A Fish dip or bath in Mebromin, Potassium Permanganate, or Methylene Blue (not to be confused with malachite green) has also helped speed cure in most instances for my clients fish (or my personal fish) and SHOULD BE part of most Columnaris Treatment regimens!
In fact with many instances of Columnaris the Methylene Blue Bath (or the even more strong, but more carefully administered Potassium Permanganate bath) was the main factor of treatment that affected a cure as per many tests.
See the picture above/left for a Betta also displaying secondary Fin Rot that literally was on "deaths door" (laying on the bottom with little response) that recovered with a treatment regimen of Kanamycin & Salt as well as regular fish baths which included Methylene Blue, Salt, and Kanamycin.
The Bottom line is a Fish Bath and maybe a swab too is a MUST part of any moderate to serious Columnaris infection treatment!
With Methylene Blue or Potassium Permanganate I prepare a double strength bath and place the fish in this solution for 30 minutes).
Please see this article for more about Baths:
As well as the above noted baths, direct applications (swabs) of Methylene Blue for mild cases of Columnaris applied to external areas of infection can help with recovery.
Reference for use of Hydrogen Peroxide: Aquarium Medications 3, Hydrogen Peroxide
Many fish diseases, it should be noted, are caused by different bacterial or fungal pathogens that often exhibit similar symptoms, so identification of a specific bacterial or fungal pathogen is not often possible from mere visual inspection of the symptoms on the fish.
By using broad-spectrum treatments such as a Furan Two & Kanamycin COMBINATION against diseases with similar symptoms affecting fish, precise identification of specific bacterial or fungal pathogens causing the disease that often display similar symptoms may not be absolutely necessary.
Please note that the combination of BOTH Kanamycin AND Nitrofurazone MUST be used for effect against true flavobacterium columnare infections, otherwise the minimum inhibitory concentration (MIC) values of these medications individually is too low.
I have also noted reports that while I have enjoyed good success with the above treatment method, assuming water parameters were spot on (including Redox and water temperature), that the failure rate is increasing.
Since the use of Nitrofurazone/Kanamycin is a synergistic combination, improving synergistic combinations via new research into human antibiotics resistance is yielding some interesting results with Oregon Grape Root which aids in antibiotic effectiveness as it contains a specific multi drug resistance pump inhibitor (MDR Inhibitor).
Reference: Oregon Grape Root - It could save the world
With severe quick moving Columnaris infections that have entered the bloodstream via a gill infection (as noted earlier in this article), combining Kanamycin, Nitrofurazone and Medicated Wonder Shells is a strong option that address mineral Cations and also helps with osmoregulation and blood issues. Unfortunately once this infection goes systemic, the odds are bad, but this is one of the few viable options at this point (assuming all stressor corrective issues have already been addressed).
Ciprofloxacin can be an effective synthetic broad spectrum antibiotic against gram-negative bacterium such as Columnaris and can be used in tank or in baths.
Triple Sulfa may also yield positive results for treatment of Columnaris if used early (although this is not as effective of a treatment for Columnaris as it used to be or as the Kanamycin/Nitrofurazone combination). If Sulfa drugs are combined with Trimethoprim, this also yields a more synergistic effect that can and does work well in cases of Columnaris that does not respond to the Nitrofurazone/Kanmycin treatment. The only caution is that Trimethoprim can be a problem with fish with large bleeding sores, so if such sores or similar are present, it should not be used.
My professional use of Triple Sulfa has found that it is occasionally a good choice along with baths and some salt for mild to moderate infections and is rarely harsh on aquarium environments including plants.
Pimafix can aid as a natural "in-tank" treatment for VERY MILD cases of Flexibacteria in combination with lower temps, salt, and baths (I would NOT recommend it for more moderate to serious cases). Do not confuse Melafix with Pimafix, as Melafix is more of an antiseptic with no effect on Columnaris whatsoever!
Unfortunately, there is much unfortunately posted in forums or websites about the use of Tetracycline or Oxytetracyline for the treatment of Columnaris however this is based on old research and misunderstanding of the large Tetracycline class of medications.
ADDITIONAL FOLLOW UP TREATMENTS;
Among other treatments I have used, especially to prevent reoccurrence once the fish are OK might include “Medicated Wonder Shells”, which contain Acriflavin (as well they contain Methylene Blue).
Product Resource: Medicated Wonder Shell; ONLY available at AAP
FINALLY, in summary of treatments; one aspect I found over and over, including when I have compared notes with other aquarium maintenance professionals is that attempting to mix a little of one method of treatment with another almost always results in failure.
PREVENTION & FURTHER COLUMNARIS (Flexibacter) INFORMATION:
Flavobacterium columnare gained the nick name “Columnaris” because wet mounts of Flexibacter prepared from diseased fish appear as column-like, "haystack" colonies.
As well; crowded conditions (often in re-circulating systems), aggressive inhabitants, poor handling, poor Redox Balance, sudden temperature spikes (or prolonged temperatures much above 80F), and the stress from high bio loads are all conditions that can allow for an opportunistic Columnaris infection.
Please note; high bio loads is more symptomatic of Aeromonas or Saprolegnia infections.
Reference: Aquarium Redox Balance
Columnaris bacterium have caused problems for fish farmers for many years. It is not easy to control, and because the disease is related to stress, an effort to identify and correct the source of the problem is necessary to prevent excessive or chronic mortalities.
Fish are particularly vulnerable to Columnaris following handling and transport, especially since Columnaris is opportunistic warm water pathogen that is often always present in the water, it simply needs an “opportunity” to become pathogenic.
Abrasion from nets, transport, crowding, aggression by tank mates, and adverse water quality conditions (such as lack of necessary electrolytes/minerals) create a situation which is very conducive to Columnaris outbreaks.
*Positive Ionic Composition of the Water & GH: this is a little more complex than this article will deal with, however this is related to both the GH and Redox. In a nutshell MG++ (positive magnesium ions) and CA++ (positive calcium ions) play a part in adhesion of Columnaris by reducing surface potential and repulsive forces.
*Redox Balance; although not generally a major concern for the average aquarist, it is important to understand when problems persist especially since newer research shows its importance in disease prevention. This is an important consideration for an aerobic bacterium such as Columnaris, since often other more obvious water parameters may be good while this one is not.
Redox balance is related to GH (although if all positively charges ions are lost from calcium and other minerals that make up GH, you can still have a higher GH of say 300 ppm and still have a poor Redox Balance).
While Columnaris Bacterium certainly need these minerals, so do fish and to make the strange leap of thought to state any GH over 50 can lead to Columnaris. This is simply bad science, not to mention proves a lack of practical experience on the part of authors of these articles.
Please Reference: Aquarium Redox Balance; Importance in Fish Disease Prevention
* Diet: many aquarium keepers may not link this to Columnaris, and in fact the link is not direct.
An optimized fish food is best that does not need to supplement with added vitamins due to "cooking out" of ingredients.
WHY? Because, as an example, excess or un-digestible protein are a common cause of kidney (renal) failure and this allows opportunistic pathogens to get a foothold.
As well, too much energy results in fatty liver issues which increases oxidative stress which then lowers disease resistance, especially to opportunistic infections such as Columnaris in particular.
My suggestion would be Clay Neighbor's "AAP Custom All Natural Optimized Fish Food"
*Consider ALL steps outlined in this article: “A Healthy Aquarium; Disease Prevention”.
The more steps you follow in this article, ESPECIALLY the use of a TRUE UV Sterilizer, the lower your chance of opportunistic disease outbreaks such as Columnaris (or Saprolegnia/Fungus).
Section Two: SAPROLEGNIA (Fungus):
Saprolegnia (often classified as a mold; from the Genus “Saprolegnia”) is often confused with Columnaris and for good reasons, they can often be similar in appearance. This similar appearance is why I combined these two unrelated pathogens into this article.
Another consideration in differentiating Fungus (Saprolegnia) from Columnaris is that Saprolegnia & fungi often grow on dead tissue, UNLIKE Columnaris which MUST have living tissue to live on.
This is an important distinction, since it is often found on dying or dead tissue of a live fish, as well as the remains of a decomposing fish, shrimp, etc.
Another noteworthy distinction is that Saprolegnia is generally a more slowly progressing disease than Columnaris (& in fact I have yet to witness a quick or especially sudden die off from Saprolegnia in my 1000s of contracted aquariums)
One more consideration for the identification of Saprolegnia/fungi is that out breaks often occur in an aquarium/pond with large amounts of decaying organic matter, with low pH, and poor circulation in the area of decay. Sometimes this even occurs in dead spots in filters such as canister filters that are not cleaned often or in under gravel filters, especially the tubular under gravel filters.
What is also noteworthy is that an outbreak of Saprolegnia can also allow opportunistic bacteria a chance to infect fish, so then you have a double problem.
Saprolegnia is not a true fungus (fungus are from the Kingdom “Fungi” such as Oomycetes), while Saprolegnia are from the Kingdom “Protoctista” which is a catch all Kingdom for the multicellular organisms which don't fit into the Animal, Plant, or Fungus Kingdom. This includes molds, green algae, red algae and more.
These organisms, considered to be saprophytic "water molds," are a normal, ubiquitous component of aquatic ecosystems (Saprolegnia are present in ALL aquariums and ponds). Saprophytes live off of decaying organic material.
Saprolegnia will often get started if there is a large amount of decomposition of nitrogenous organic material such as dead fish left in the aquarium or large amounts of high protein fish food such as krill/shrimp. Injured fish with open sores will amplify this potential problem.
While the raw shrimp or similar cycling methods have their risks for allowing a foothold for a Saprolegnia outbreak, this does not translate to dried or prepared food unless it has an outward growth of "mold" on it, and even then based on my experience, it would be just like cheese in that removing the mold, removes the threat.
Please read further about the lifecycle of Saprolegnia zoospores to also explain the risks, as well as the references.
Further Reference: The Aquarium Nitrogen Cycle; Raw Shrimp Cycling
Treatment of Fungus/Saprolegnia is somewhat similar to Columnaris, although Saprolegnia responds well to these chemical remedies that are not generally effective for Columnaris (as well as a few antibiotic/organic remedies):
Please note that many of the above remedies can be combined for more strength, however others cannot, such as the oxidizers (Potassium Permanganate or stabilized oxygen chlorine).
Salt, dips, and baths are also effective (in serious cases essential) as part of a Saprolegnia treatment.
However treatments often useful for Columnaris such as Kanamycin are less effective for Saprolegnia/Fungus.
As for Erythromycin, I have read many fish keeping articles (especially on Betta forums) where Erythromycin (aka Maracyn) is recommended for Fungus (Saprolegnia); This is simply WRONG! While Fungus is not a bacteria and so cannot be labeled as either gram positive or gram negative; the fact is gram positive medications do not treat true fungal/saprolegnia infections and even if this is a misdiagnosis with Columnaris, this is still incorrect since Columnaris is gram negative. Sadly this misinformation is cut and paste around the Internet resulting in many needless fish deaths based on my experience and emails!!
Saprolegnia (fungus) can be even more opportunistic in poor water with stressed or injured fish than many bacterial infections such as Columnaris, so healthy water conditions are even more important for cure (& prevention) and if water conditions are poor, all the medications in world may not affect a cure!
The obvious 0 ammonia/nitrites are important but so is the often forgotten GH and a stable pH (provided by a proper KH for the fish kept). Without adequate calcium (found in GH) your cure will be difficult to achieve. Medicated or regular Wonder Shells may help in this area.
Also important is a clean tank without organic mulm buildup, so make sure there is NO decomposing organic debris which can by itself bring on a Saprolegnia infection, in fact I have documented this which is why I generally recommend against using raw shrimp to start your nitrogen cycle.
This article about aquarium cleaning may also be useful:
Prevention/Lifecycle of Saprolegnia
The lifecycle is best described this was: the asexual spore of Saprolegnia release motile, primary zoospores.
It is these Secondary zoospores which are considered the infectious spore of Saprolegnia and can reside in grave/substrate, filters, and the water column for some time until this host is found (these spores do NOT require a food source during this time as well). Repeated vacuumings and large water changes can reduce this number but not totally alleviate it unless the tank is sterilized with bleach (especially since these spores can reside anywhere in an aquarium), so denying the zoospores a host via healthy, non stressed disease resistance fish is the next step.
KEY POINTS ABOUT SAPROLEGNIA/FUNGUS FOR PREVENTION AND TREATMENT
For further reading about Saprolegnia, please read these outside resources:
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