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TB in Fish, Mycobacterium Tuberculosis; Bettas & more
Fish Tuberculosis is generally caused by Mycobacterium marinum, a bacterium closely related to the human TB (Tuberculosis) bacteria, Mycobacterium tuberculosis, although incidents of Mycobacterium triplex have also been reported with Bettas
Despite some internet claims, based on my many years of "house calls" and other professional aquarium maintenance work has shown Fish "TB" to be relatively uncommon with the exception of cases where the bacteria has been passed around and the fish' immune system has been compromised, this is especially the case with Mycobacterium triplex.
Be careful about assuming your fish have Fish TB, unless all symptoms are present and treatment for more likely infections have failed.
However Bettas and Gouramis for reasons not 100% known seem to be more susceptible or have been placed in conditions where tuberculosis is more likely to overcome the fish' immune response.
Please read the "PREVENTION" section for more about TB in Bettas in particular
Treatment for Mycobacterium tuberculosis is often long and not always successful, as well low fish immunity due to poor aquarium parameters (including Redox Balance), along with fish age or even simple stress from tank mates can add to treatment difficulties or make treatment impossible (especially since Fish TB is difficult to treat anyway)
A myth I have seen written in a few "circles" (for some reason I have found this myth especially common on certain Betta Forums), is that Fish TB can also cause full blown human TB which is simply not true (only mild localized infections in healthy adults humans).
However it is still best to avoid fish to human transmission, especially if your immune system is compromised in any way. Generally when the Mycobacterium marinum bacteria infects humans it is a dermatological issue as the bacterium usually enter the skin via small abrasions or cuts when you are performing aquarium maintenance. The symptoms in humans are usually restricted to skin and soft tissue destruction in most instances of Mycobacterium marinum infection via small purple lesions that can gradually grow.
Another myth about Fish TB, especially since it seems to have become the aquarium fish disease "De Jour" (disease of the day), is its transmission.
Based on emails, phone calls and discussions with my maintenance friends, you would think every fish that is sick now suddenly has this disease.
While it certainly seems to be more common and virulent as per confirmed cases, it is NOT commonly present in an aquarium (unlike Aeromonas, Columnaris, or Pseudomonas bacterium).
So in the case of fish that have been living in an aquarium for months and often years without any outside exposure to other fish, the facts are it is impossible for the fish to suddenly come down with a Mycobacterium infection.
Usually this false diagnosis with no history of possible exposure is simply the result of a simply weak or old fish showing symptoms that are often common to Fish Mycobacterium (TB).
Even with potential exposure, in my experience with confirmed cases of Mycobacterium, transmission usually ONLY happens in aquariums with old, genetically weak, injured, or with poor tank water parameters (which includes a poor aquarium Redox Balance).
In other words, under normal conditions this is not a highly contagious fish disease!
If staining for identification, Mycobacteria stain bright pink against a blue background (as these bacterium are acid fast).
However, most aquarium fish keepers do not have the ability to grow cultures or make slides; so the symptoms of Fish TB are usually wasting away, lesions on the fish' body, loss of scales and/or coloration, and especially skeletal deformities such as curved spines.
The fish in the picture above (please click to enlarge) displays classic symptoms of Fish TB in finage, skeletal deformity, and wasting to the point light can slightly penetrate her abdomen as seen in the light spot.
Mycobacterium triplex can only be identified by 16S rDNA sequencing, so positive identification is difficult.
Time of Treatment is VERY long and is generally administered for at least three months.
A hospital tank treatment is advised for fish TB since this generally is a very long treatment regimen and a three month treatment of ANY antibiotic can result in serious damage to your aquarium bio filter.
The three most proven antibiotic methods are (which can and should be used in a combination of two of these drugs along with the other described alternative treatments):
A forth consideration, albeit less filed tested (it does show lab results though) is Usnea, which from my experience should only be administered in a "Fish Bath" form for 30 minutes. Methylene Blue should also be used in this bath, but no other antibiotics should be used in this bath with Usena.
These baths can be rotated; meaning one bath with Usena and Methylene Blue and the next bath with MB along with one or two of the other antibiotics, then back to the Usnea
Usnea is best as a used as a bath ALONG with an in tank treatment with one of the first three noted medications (or better hospital tank).
And finally, a fifth consideration is Allicin, the active ingredient in Garlic. Mycobacterium marinum) has been demonstrated to be effectively treated with Allicin.
SeaChem Garlic Guard can be used in a fish food slurry preparation and mixed with both Neomycin and Kanamycin for improving the potential effectiveness of tuberculosis treatment.
See: Fish Nutrition; Garlic
Back to Fish Baths; regardless of the medication or combination of medications used in tank, I suggest a Fish Bath with one of the first four before mentioned treatments (not garlic) at least once per day during this time period. In fact in some cases the fish baths were all that was needed for success assuming these were carried out regularly.
Now for the bad news, from mine and others experience, once the fish became emaciated I and others had little to no success saving them.
Please Read/Reverence these Articles:
*Aquarium Medications, Information
*Fish Baths, How to Perform
Treatment of Mycobacterium triplex in human studies has shown it to be nearly impossible with only reduction of symptoms, not eradication of the bacterium. These treatments used levofloxacin, ethambutol, and clarithromycin; all of which not available in fish medications.
You best bet with this rare strain (assuming your fish even has it), is to sadly euthanize and sterilize EVERYTHING, then start over.
How NOT to Treat:
The use of salt either in baths or in the aquarium will have absolutely no affect on Mycobacterium tuberculosis since this bacterium thrives equally well in salt or freshwater.
Temperature increases or decreases have little effect and in fact a temperature increase over 30°C. (as with Columnaris) often worsens a Mycobacterium tuberculosis infection.
Temperature decreases has shown some anecdotal slowing of the progression of Mycobacterium tuberculosis, but no cure.
There is not a 100% proven way to prevent Aquarium Fish Tuberculosis (as with most pathogens), however based on my own observations going back to 1977 (working at a Pet Store Fish department and then my aquarium maintenance company), I definitely noticed patterns. Emails from customers and questions I see asked in forums and elsewhere have added to this same pattern.
One pattern is what I noted earlier and that is Bettas and Gouramis have a higher incidence of both suspected and proven cases of Mycobacterium marinum Tuberculosis infections.
I also noted that certain vendors (wholesale suppliers) would have a higher incidence of TB infected fish, so avoiding the purchase of fish from places that you have suspected TB on numerous occasions may also be helpful; this said, do NOT write off a retailer or vendor based on 1 or 2 suspicions of Fish TB, as it may have been another disease pathogen, as well frankly no vendor/retailer is perfect!.
Also be careful with Betta shows or similar, as I believe that this is both a major stressor AND infection point. As for procedure you can do to prevent Fish TB infections; there are many.
The most obvious is as stress free an aquatic environment as possible since stress due to many factors seems to be a major factor based on my work and research. This includes stress from water conditions and tank mates.
Changing water regularly, maintaining a stable pH & KH, near 0 ammonia (NH3) and nitrites, a balanced Redox and ESSENTIAL aquarium positive mineral ions.
The use of Aquarium UV Sterilization with a correctly applied UV Sterilizer performing at Level 1 Sterilization (this will NOT and CANNOT be achieved with the many low end UV Clarifiers such as the Green Killing Machine, AquaTop Hang On and similar water clarification ONLY devices flooding the market!).
The correct use of a UV Sterilizer can aid in Redox Balance and in the end also aid in fish immunity.
The use of SeaChem Garlic Guard or similar in fish food can also be used in an ongoing basis to improve fish health and prevent Fish Tuberculosis.
Back to Bettas in particular, a problem I have seen based on patterns that are almost 100% identical and that is many Betta Forums and Clubs will pass around the same methods of Betta keeping that can increase the likelihood of TB infections.
This includes constant chasing of pH, 100% water changes, keeping of Bettas in very small closed environments, lack of positive mineral ions essential to immune response, passing around fish (with constant exposure and stress), and limited gene pools due to interbreeding.
My suggestion is to keep your Betta in a system with a larger volume of water with mall individual containers.
Within this system these practices can aid in TB prevention:
- Good bio filtration with sponge filters, even better Fluidized Sand Bed filters, use of products such as SeaChem Purigen to further "clean" the water
- Maintenance of a stable pH & KH with as little of an effort as possible using products such as Alkaline Buffer, Acid Buffer, Driftwood, Frog Moss, blended RO Water; IF NEEDED!
- Constant drip of mineral ion replenishing products such as SeaChem Replenish, or more simply with Wonder Shells. As well to not be overly concerned with GH.
- Do NOT pass your fish around in environments out of your control and attempt to bring new fish into your breeding
- Utilize a GOOD UV Sterilizer such as the TMC Vecton at level 1 Sterilization.
If you are breeding Bettas, keeping the Bettas within isolation boxes/containers with a much larger 'cubical based centralized system' is a practical way to utilize a good UV Sterilizer, as well as maintain much better water quality.
The picture below displays aquarium cubicals that I highly suggest for anyone serious about breeding bettas so as to be able to maintain more stable water quality and also utilize UV Sterilization.
These cubicals can be placed in larger aquarium and can also be blacked out to prevent interaction between Bettas. However the cubicals do allow for interaction of "smell". My suggestion for this is to keep certain Bettas at different points in their breeding cycle together in the same aquarium system (in other words multiple systems
See also the articles below in the references/resources dealing with Aquarium Disease Prevention for more help in Fish TB prevention
*Aquarium Disease Prevention; Proven Steps
By Carl Strohmeyer
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