Columnaris. how long can it survive with no hosts?

My understanding is it is pretty much always present. I've seen websites say a month or two months but I suspect that just reduces the bacterial count.

Mainly it's just fish are always healthy although I'd imagine sterilising a tank before hand would kill most of it off.

I had one summer where I got it twice about 3 months apart I think. Lost entire schools while other fish showed no signs of it. Uv unit made no difference.


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90 days Fishless ,would allow for focus on plant growth and maybe a few cheap test fish such as danios or tetra's to gauge whether there is still an acceptable risk after the 90 day's.
Is not a long time from plant perspective.
If the tank were smaller than say 55 gal,then I might consider it time/excuse for re-do.

thanks for the comments

True columnaris seems to be one of those wild cards that is difficult to fully eradicate. I wouldnt feel comfortable just waiting for X amount of time and assuming its gone. I'd use bleach on everything just to be safe.

From what I've seen and heard, it never truly goes away. Sources online say that it is found in nearly every aquarium, but rarely becomes a problem. From what I've seen, this is mostly true, however, I suspect that there are different strains of the bacteria, as well as healthy levels to expect in a tank. It's probably similar to the strains of E Coli that live in our guts, a fair amount can be present without any problems, but too much, and you can get an outbreak. If you're worried, daily salt dosing works fairly well to control it, and eventually the salt will reach a level high enough to kill the columnaris. lksdrinker is right about it being a wild card, it may lie dormant forever, without causing any problems, and it may spring up out of the blue and kill all the fish in your tank. From what I've seen, reducing stress in the tank inhabitants is the best way to prevent an outbreak.

Have only ever introduced it by adding new fish without quarantine.Tank's run fine for month's/year and then a few new fish added and have been bit more than two or three times.Anybody else seen it appear without new fishes added recently?
I would agree with salt but..plant's won't handle much salt very well IME
Smaller tank than 55 gal as mentioned,I would just tear down.

My tank is 120x45x45. Its my first tank and pretty big and im loath to tear it down. Besides im not even sure if its columnaris. Maybe fin rot. Or tetra desiese. Or maybe simply an unstable tank after 3 months. my fish keep dying 1 by 1.

Best way to clean it is to do a thorough alcohol wipe, then bleach.
There can be biofilm on the glass that will withstand short term bleach exposure, the alcohol will wipe it off, though.

As someone said, you can always test the waters with feeder guppies.

Main thing you can do to keep fish healthy apart from feeding quality dried and live food. Is to do weekly water changes of between 40 and 50% and make sure you use a quality dechlorinator like Prime that will treat free chlorine as well as chloramines.
This is 90% of what fishkeeping as all about, the other 10% you get to watch the fish and wonder if it is time to repeat the cycle yet.

I have used Seachem Kanaplex in the past for columnaris in a guppy breeding tank... I still lost all the infected adults, buy once the treatment cycle was complete the fry survived, grew out and became prolific.

Was a 20 gallon long though, 55gallon is fairly large.. should still be treatable though.