# [Wet Thumb Forum]-Fish TB, mycobacteria and hospitalization



## flagg (Nov 29, 2004)

In a previous discussion, Diana wrote:

Folks, there are a lot of aquarium fish out there carrying diseases. The worst disease, because it often doesn't show symptoms before the fish dies, is Fish TB. 
One random survey of over 300 aquarium fish (from stores and hobbyist's tanks) showed that the majority of fish were infected with mycobacteria. Whether the infected fish dies after you get it in your tank will depend on:

species of fish
strength of the fish's immune system
virulence of the mycobacteria strain
luck
stressful conditions

So I was wondering, should we be hospitalizing and medicating our fish against mycobacteria prior to introducing them into an aquarium? Now, I know from her book that Diana does not like to add new fish to an established aquarium, but what about the folk who do? Should they automatically hospitalize new fish to treat for TB or any other illnessess? Or how about when setting up a new tank just to make sure that one has healthy fish right off the bat? Or would all this hospitalization and treatment lead to bacteria strains w/ stronger resistance to antibacterial medications?

Interested in hearing peoples thoughts about this....

-ricardo


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## dwalstad (Apr 14, 2006)

Dear Ricardo,

Fish TB is incurable. Believe me, if there was an antibiotic that worked, we would all know about it! The only thing that looks promising to the fish industry is a DNA vaccine, but this DNA vaccine is still in the developmental stage. Mycobacterial infections are currently causing major problems in aquaculture, laboratory zebra fish, tropical fish breeding farms, etc.

My tanks are all infected with virulent mycobacteria. I set up a hospital tank with antibiotics and a high salt concentration for one female Rainbowfish with a small sore. I only made the problem worse. The small sore got much larger, and was I lucky to not lose the fish. All I did was kill off harmless, competing bacteria (on the skin) that probably help keep the mycobacteria in check.

The mycobacteria responsible have a waxy outer coating that makes them extremely resistant to all chemicals and antibiotics. Mycobacterium fortuitum, which shares honors with M. marinum for creating the most havoc in the tropical fish industry, can grow in media containing 5% salt (sea water is about 3.4%, and salt treatments have an even lower salt concentration). It is no surprise that my salt treatment didn't work!

My opinion: The only thing medications do is kill off harmless competing bacteria (in the gut, on the skin, etc). Their use is counter-productive.

My advice:


Be very careful where you buy your fish.

Instead of wasting time and money on antibiotics, consider getting a UV sterilizer (it saved my fish)

A 3 week quarantine is pointless for a disease like Fish TB where even the healthiest looking fish may be infected (Frequently, infected fish will develop immunity, survive, and look totally healthy from the outside). So don't add a newly purchased fish to the main tank. Instead, put it in a quarantine tank containing a fish from the main tank that you know is healthy. I would wait at least 8 weeks. This is usually enough time for a vulnerable fish (hasn't been exposed to this virulent mycobacteria, so it has no protective immunity) to succumb to a highly virulent mycobacteria. Better to risk losing one fish than introduce a virulent mycobacteria into the main tank and kill all the fish. If the healthy fish does okay, then you can be pretty assured that the suspect fish will not create havoc when it is introduced into the main tank.


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## javalee (May 8, 2006)

Mycobacterium such as TB are particularly difficult to wipe-out (hence the 9 month antibiotic treatment plan for humans with TB) so you aren't gonna help fish with this illness.

Considering the worsening picture of antibiotic resistance in the world, people shouldn't be using antibiotics to treat pet fish anyway. I don't mean to sound harsh, but truly, doctors are facing a real crisis these days with resistant infections caused by the overuse of antibiotics and are being taught to hold back on them when able. Please, the moral thing to do is to save antibiotics for really sick people.

I personally bought an oto that quickly succombed to TB (curved spine etc) and honestly, I'm sure all my fish are infected now, but thet're not sick(this oto died 6 mo. ago)! The important thing to realize is that these bacteria are pervasive (as Diana said) but that the infection does not cause illness except when a fish is otherwise stressed (transport, malnourished, another infection).

The best thing you can do is keep your fish happy and healthy with a good diet.


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## javalee (May 8, 2006)

Sorry Diana, I must have written the above as you were posting yours.


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## dwalstad (Apr 14, 2006)

Dear Javalee,

Your letter provides one more good reason for not using antibiotics to treat mycobacterial infections. I couldn't have said it better!









Folks, Fish TB is so common in the hobby now that if you have a sick fish and you don't know what the problem is, there's a good chance (70% I'd guess), that the fish is infected with mycobacteria.

Bottom line: antibiotic treatments for sick aquarium fish are generally useless, may be counter-productive for the fish, and promote (as Javalee wrote so eloquently) antibiotic-resistant strains of mycobacteria.


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## Miss Fishy (May 13, 2006)

I did some research on Fish TB on the internet, but I found conflicting answers to all my questions. I was wondering if someone here could answer them or tell me of a reliable book or website where I could find more information.

Can mycobacteria live on creatures other than fish, or do they need a fish host? Can the bacteria be transferred in water or on plants, or do fish actually need to come in contact with an infected fish to catch this disease? Can humans catch it?

I bought some Golden Medakas (_Oryzias latipes_) in February which came with a severe Gill Fluke and Tapeworm infestation. It did not become apparent during their quarantine period so one of my other fish came into contact with them (luckily he is fine). As soon as I saw them scraping their gills, I removed them to a hospital tank and treated them with Praziquantel. The parasites have now been gone for three months, but although the fish look healthy, their odd behaviour has not improved at all, and two have died during this time. They spend most of their time resting in the plants, and have become so nervous that they hide whenever I come into the room. The two that died looked fine, and then over a few days they developed pale colouring, arched backs, the odd white sore or bloodspot, then had trouble swimming. Of course these symptoms could be any number of fish diseases and the fact that my other fish did not get sick suggests that it isn't Fish TB, but I was just wondering whether I should take any extra precautions such as wearing gloves when I put my hands in their tank etc.

From Alex.


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## dwalstad (Apr 14, 2006)

Dear Miss Fishy,

I've tried to answer each of your question within the body of your letter:



> Originally posted by Miss Fishy:
> I did some research on Fish TB on the internet, but I found conflicting answers to all my questions.
> 
> ***Not surprised! When I get home I'll post some websites. Many are from fellow Australians who've run into problems with this disease.
> ...


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## Miss Fishy (May 13, 2006)

Dear Diana, 

Thank you so much for your replies. I thought it was too good to be true when I read on a site that mycobacteria could only live on a fish host. Since I put some plants from the sick fishes' tank in my ponds before I realised they were sick, the bacteria may be in all my tanks and ponds by now, transferred by birds, insects and live food. 

I will now be very careful when handling my tanks and ponds and always wear gloves. I am more at risk since I have CFS/ME (known as CFIDS in the USA). On top of that I always have cuts on my hands because I am always hurting my hands due to muscle weakness. 

That makes a lot of sense that the parasites were a secondary disease, and explains why the Medakas are still ill. I hope that with good food, good water conditions and as little disturbance as possible, the last three will survive. Luckily all my other fish are fine. Either they were healthy enough to resist the bacteria when exposed to it for the first time, or else they had already built up a resistance to it (they all came from commercial aquarium shops and I buy plants from many different sources). 

From Alex.


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## dwalstad (Apr 14, 2006)

Here are a few websites that will give anecdotal information from those who've had a run-in with mycobacteria and Fish TB...including yours truly. For Miss Fishy, two of the spokesmen are from Australia. But this disease is world-wide fueled by imported fish from farms that are breeding infected stock and selling chronic carriers. Touchy, highly political subject, which is why you don't hear much about it.

But if any of you've ever bought a guppy and wondered why it didn't last more than two weeks, there's a reason. Back in the 50's I remember when I could buy a female guppy from a store, and it would have 50 babies then do fine for a year or more. Those days are gone and there's a reason....

My apologies for not being able to make Internet hyperlinks for the 3 websites below. Perhaps Robert H. can come to our rescue.

Websites:

http://pandora.nla.gov.au/pan/21803/20040913/members.op....au/chelmon/Myco.htm
Adrian Tappin's excellent article about mycobacteriosis in Rainbowfish

http://www.reefkeeping.com/issues/2003-07/sp/feature/index.htm
Steve Pro's article on human infections with saltwater mycobacteria; remember that various strains of mycobacteria operate in both freshwater and saltwater

http://users.bigpond.net.au/paul.byham/angfavic/vicnews.htm (see the article by Colin Trneny in the Dec 2004 issue of the VIC newsletter about prevalence of mycobacteriosis infections in Australia)


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## Christian Hansen (Apr 27, 2006)

Hello Diana
When on the subject, I wondered....Do you use gloves etc., when having your hands in your tanks? After having read the article resulting from the second link, I was a little suprised hehe.....If I think of how many hours in total I have had my hands soaked in fisk tank water, Im suprised that I havent had any trouble. The article makes it sound very likely that the fish TB will infect humans if one is messing around in the tank with bare hands.
Furthermore, the article states that the bacteria causing the TB can be found in soil. Do you think that the soil substrate increases the risc of getting TB into ones tank ?

btw, just got your book, and am in the progress of reading it. Until now it seems like the best fisk tank related book I have ever bought. Its so nice to have a book that goes into fine details on a subjects. I am pretty tired of purchasing books that are merely overviews with a bit of "not very detailed" information.


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## dwalstad (Apr 14, 2006)

Dear Christian,

Glad you are enjoying the book.

As to Fish TB, this is a new subject for me, so what I write about it here is not "set in stone". Please make allowances.









I don't wear gloves when I work with my tanks. Too cumbersome! However, I do wash my hands and rinse whatever part of my skin contacts the tank water. If I had an open sore, I probably would not clean the tank that day.

My fish have an officially diagnosed case of fish TB (I took a couple of suspicious fish to the local fish veterinarian). So I know that the water does contain infectious mycobacteria. Thus, the precautions I take are not just whimsical.

Soil does contain mycobacteria. However, I believe that these soil bacteria will not cause mycobacteria problems. The virulent mycobacteria that will cause problems are those that have been passed for years through an animal (i.e., the fish host). The Mycobacterium fortuitum that has been living for centuries in the soil is probably harmless. However, the M. fortuitum that has "set up shop" in a tropical fish breeding farm is an entirely different matter. As the years pass, this bacteria has learned to evade the fish's immune system with various mutations. It has become increasingly virulent to fish...and to humans. Virulence has to do with the bacteria's ability to survive and multiply in macrophages (key components of the immune system on fish and humans). One leads to the other.


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## Miss Fishy (May 13, 2006)

Those websites are very interesting. Now I come to think of it, I read the one from ANGFA Victoria early this year, but I had completely forgotten it. I'm going to ask the vet to order me some arm length veterinary gloves that I can use when I need to put my arm in the tanks. They are made of thin plastic, so should be good for fiddling around with scissors and small plants.

Since the disease is so widespread, I think it's likely that my tanks and ponds already had the bacteria before I got the infected Medakas (assuming that Fish TB is indeed the cause of their problems). Over the years I have bought fish and plants from many different shops, some of which import fish directly from Asia, and all of which sell Rainbowfish in varying states of health. Also, in 2001 I bought some Guppies that died mysteriously, only a week after I put them in my first and last tropical tank (the heater broke soon after).

Perhaps the fact that my tanks are coldwater and are _very_ lightly stocked with fish that are fed a good, varied diet has helped avoid an outbreak of mycobacteria. Probably I've just been very lucky!

From Alex.


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## flagg (Nov 29, 2004)

Wow! I never expected such a response to my post! Thanks to everybody for their input and especially for the links to other sites that discuss fish TB. From all I've read, it seems like the best suggestions (in a nutshell) are (1) to quarantine all new fish for 2 months w/ an "old" healthy fish to see if any get sick, (2) not to use antibiotics as a treatment unless absolutely necessary (e.g. all else fails) and (3) be very careful where you get your fish from. (Please note that the MLA has declared that it IS ok to end a sentence w/ a preposition!







) Would that be a good synopsis?

On that last note of obtaining fish... would it be best, then, to obtain fish from breeders from our local aquarium society rather than our LFS? (That is, of course, for those of us who have an aquarium society in our area.)

--Ricardo


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## dwalstad (Apr 14, 2006)

You've summed up the practical advice very nicely. A few caveats:

Antibiotics haven't worked for me or many others (tropical fish farms, scientific labs, aquaculture farms, game fish hatcheries, etc). For Fish TB, antibiotics don't work.

I do recommend getting fish directly from the breeders. 

You can join a local aquarium society. I think some of the aquarium magazines list them. 

Or you can start your own club. We have one here that simply consists of going to each others homes every month or two and trading plants, fish, etc. Its fun to see other people's tanks and show off your own.

The other way is to join the organization for the fish you're interested in. There are organizations for Killifish, cichlids, guppies, Rainbowfish, etc. I don't mind paying mailing costs to get fish directly from the breeder. The fish are healthy and cheaper than from the stores. 

Some commercial sources may be okay, especially "Mom and Pop" ones that breed their own fish or buy from local breeders. WetThumb Aquatics comes to mind. Considering the prevalence and danger of Fish TB to the hobbyist, I think it is reasonable to ask sellers what they do to avoid selling fish carrying chronic infections of Fish TB.

I querried one Internet vendor that advertises selling healthy fish. They said they give the fish (many from Asian fish farms where TB infections are the norm) a two week quarantine. The vendor does no screening for TB, nor do they buy from farms that monitor for TB. 

As hobbyists become more aware, I hope that fish sellers that do take precautions will get the recognition and business they deserve.

I remember a time when you could buy healthy fish from aquarium stores.


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