Hi all, I’ve seen some prior threads on fish TB here and the general consensus seems to be very rare. I was wondering if anyone has thoughts on this piece by Walstad? Exec summary - mycobacterium / TB are highly common in the ornamental fish world and account for a significant fraction of unexplained fish deaths. Posting in apistogramma as I wanted to know if anyone had experience with fish TB in apistos.
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Mycobacterium (TB) and apistogramma
- Thread starter Andrew H
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Not me, at least yet (knock on my wood block head). This is a prime reason I quarantine every fish for at least 4 - 6 weeks before they go into one of my community or breeding tanks.
I've had trouble with this several times over the years and have never been able to figure out a treatment that works. Once I lost nearly 1,000 Apistos across 15 species that were ready to ship. I had not added anything into the fish room for months so I don't know what triggered it. It moved through every tank and wiped out 95% of my fish. I lost 8 species completely.
I had fish examined by a fish health pathologist with the US Fish & Wildlife Service so I'm pretty confident about the diagnosis. Nothing I did reduced the problem. I did everything I could to keep it from spreading, sterilizing nets after each use, sterilizing siphon tubes, gravel cleaners, etc. Nothing worked. As an experiment, I kept one tank on constant UV filtration for a month or more and the fish in that tank fared no better. All I could do was wait for about 6 months until there was no indications of a lasting condition and gradually rebuild my stock.
I've had a few smaller outbreaks over the years but nothing as serious as described above. In short, it can be a real problem.
One person with a reputation (on internet; but can't find the link) reported that they were able to cure TB with a very strong uv light for filtration. I forget how strong but i think it it was > 40 watts. Of course water turn over and time spent under the tube will have a impact on uv effectiveness.
Wow, that’s terrifying. Curious about how one goes about getting a fish necropsy? And it sounds like the infections just burned out and you haven’t seen it since?
I think you’re probably referring to the article I linked to - Walstad.
30+ watts are necessary for any UVC to work properly relatively independent of turnover. And I doubt it's contributing to healing infections. UVC has a good impact on infection rates, though. Across the board for any bacteria and parasites with free swimming life stages.
The only time I had to do with a proven case of Fish-TB was when I was still involved in breeding Malawi and Tanganyika cichlids. Back then we had the commercial interest warranting a clinical analysis.
The detection and the verification of Mycobacterium marinum (fish-TB proper) is the biggest problem. The typical home aquarist is quick to diagnose it thanks to Doctor Google, but is there a verification? Usually not. And in many cases I have read reports on that assumed fish-TB and actually hat a laboratory verification done, Mycobacterium was present, but not the cause of the infection. Often it's an opportunistic bacterium out of a myriad of possible species and strains.
I think this is the reason one can assume the incidence lower than the fishkeeping community is expecting.
The same goes for other virulent bacterial diseases: Neontetra disease or true Columnaris for example.
There is only one disease I deem all around problematic in the trade and thank the gods it barely touches cichlids or characins: EUS (epizootic ulcerative syndrome) aka dwarf gourami disease aka dwarf gourami iridovirus (DGIV). That stuff is nasty after all my experiences with it (retailers culling ALL labyrinth fish in their stock no matter what species). And it is still not clear whether it's a fungus or a virus.
I can only speak for the EU: Pretty easy ONCE you have found a veterinarian that takes ornamental fish cases. The next one I have from my place is over 100km away.
Once you have found a doc willing to take the case: Cull a specimen of your fish, freeze it, send it in. Sometimes the vet comes to your place doing that themselves and transporting the fish cooled, not frozen. Some vets do the analysis themselves, some send them in to a lab.
Usually a full analysis costs about 200-400€ including the vets time charges. So this is only really worth it, when you have a whole fishroom full of pricey species and specimens to save or you are breeding/trading commercially. The average home aquarist with 3-4 display tanks and maybe one breeding project will have to consider the proportionality. Even if you are endeared with your fish... if they are common species or even domestic breeds one should reconsider the decision.
I was fortunate to have a professional connection with the fish health center near me and they did the examination which was only observational. They didn't make any effort to identify specific pathogen. they just told me it was Mycobacterium.
Yes, at that time the disease worked its way through the fish room and disappeared. It took over a year before I was able to bring in new fish and I didn't distribute any of mine for nearly 2 years.
You're welcome, but I'm not Max, it's Mac.
Lazy buggers... sorry, that's almost grossly negligent for an official eco-safety and health institution. Here proven cases of Mycobacterium have to be reported. So if the suspicion is there the pathogen is usually identified.
Damned phone keyboards! Note that I’ve corrected the record. Thanks to all for the feedback on this. I actually have access to the tools to ID the bacterium (molecular biology stuff) but not the ability to do the examination. Evidently granules in the organs are the indicator.You're welcome, but I'm not Max, it's Mac.
The histopathologic hallmark of mycobacterial infections is granulomas, which can be seen under the microscope. Inside the granulomas, the bacteria can be seen and stained with something called acid fast, which turns them purplish red (this is another hallmark of mycobacteria).
I found this article which showed a gross specimen of a fish's spleen when infected with mycobacterium marinum, and you can see white nodules in the spleen. You can also see some microscope images of what granulomas look like and the bacteria stained with acid fast! https://eafp.org/download/2014-volume34/issue_4/34-4-124-Avsever.pdf
I think you'd have to culture a nodule to be 100% sure what type of mycobacterium it is (I guess there's a couple species that can infect fish). Myocbacteria is really hard to culture in general. But, seeing granulomas and acid-fast bacteria under the microscope is pretty good evidence that the fish was infected with a mycobacterial species.
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As a non fish enthusiast, only here to take care of spammers, you've got my curiosity fired up. How is this pathogen passed from tank to tank seeing as how all precautions seem to be taken?
I don’t know very much about mycobacterium marinum, but mycobacterium tuberculosis can lie latent inside a person for many years and then be reactivated later when a person becomes immune suppressed. Many people have lung nodules from latent TB and don’t know it. Maybe it’s similar for fish?
This article is fascinating for anyone interested in transmission - scroll to the epidemiology and prevention section: https://journals.asm.org/doi/10.1128/microbiolspec.tnmi7-0038-2016 .
It discusses how M. marinum can remain viable in soil and water for up to 2 years, which is frightening. However, they also state that UV sterilization of water can kill M. marinum and provide a source for this datapoint (I didn’t read that article).
It discusses how M. marinum can remain viable in soil and water for up to 2 years, which is frightening. However, they also state that UV sterilization of water can kill M. marinum and provide a source for this datapoint (I didn’t read that article).
