Re: [RML] Tropical Fish Granuloma

Adrian R. Tappin (atappin at ecn.net.au)
Tue, 16 Jun 1998 15:09:55 +1000

At 13:32 14/06/98 -1000, Mach wrote:
>Allmost the same thing that the vet that deals with fish here in Hawaii
>said. It is everywhere. It can be present on plants, moist areas,
>anything. There is allomst nothing we can do about it. More importantly
>is to determine the conditions that makes M. marinum pathogenic. It seems
>like most of the time it is a saprophyte or weak pathogen that affects fish
>of compromised health (poor water quality (pH, ammonia, etc) over feeding,
>etc.

I agree that environmentally induced stress conditions are a contributing
factor and may well be a major factor. However, I think perhaps that this
may also be an over-simplification.

I have seen Mycobacteriosis develop under conditions that I would have
thought were perfect. Also we have cases where it infected only a few
individuals yet these same individuals shared the same parents,
environmental conditions and also the very same tank. Why then does it only
affect some and not all? If it was some immunity response then seeing that
they are all siblings you would think that they all would have the same
immunity.

I have also seen a whole population of one species in a mixed community
wiped out yet no other species group was affected.

Personally I believe that there are some other "unknown" or "underestimated"
factors and that's why I'm continuing with my quest to find out as much as I
can. If we are able to find or isolate these factors then perhaps we will be
in a better position to avoid or change the circumstances that put our fish
at risk.

An example that comes to mind is temperature - High temperatures in my
opinion is one such contributing factor. Now whether this is because the
bacteria becomes more virulent in warmer temperatures or that the
rainbowfish are under stress at higher temperatures, I don't really know -
perhaps its both? It may be that we can providing perfect water conditions,
diet etc., yet once the temperature goes above a certain level the fish are
at risk. Also how do we acquire the bacteria in the first place and can we
avoid getting it?

Adrian.
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Adrian R. Tappin
"Home of the Rainbowfish"
http://www.ecn.net.au/~atappin/home.htm
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