New syndrome?

[NetMax]

There is NTS (new tank syndrome) which is well known to almost everyone,
and there is OTS (old tank syndrome) which is known to most of the
regular readers here and experienced hobbyists, but I think I have a new
one for you to consider.

Have you heard of this scenario before? You introduce a seemingly
healthy fish to your tank (without quarantine, though I'm not certain how
effective quarantine would be in this case), and within a few days, all
the fish in the tank are dead (from bacteria and/or Ich). The common
denominator is that the hobbyist had not added anything to that tank for
a long time (over 8-9 months), and their fish were all healthy before.
This is a real heart-breaker, and to add insult, very often, the
introduced fish survives, seemingly oblivious to the carnage it has
caused.

Having heard of this occurrence from many other hobbyists (and
experienced it), I've a hypothesis which I'll call NGS (new germ
syndrome). I don't think it's as simple as the introduced fish being a
carrier. The problem is the prolonged inactivity of the immune systems
of fish which have been isolated for many months, preventing them from
reacting to the almost benign germs which are always present in normal
waterways. The human equivalent would be someone living in a sterile
bubble for a long time, who would be at a pneumonia risk from common cold
germs.

The problem is worse with fish, as they don't have an atmospheric shield
around them like humans. In nature, fish are all interconnected by
water, which is an easy conductor for parasites, bacteria etc. If one
fish is sick, they are all exposed to the same contagion, to varying
degrees of concentration, depending on their proximity to the greatest
source of the disease. Consequently, in nature, fish are always exposed
to disease, and the exposure typically ramps up (as the disease spreads).
This would require the fish (in nature) to have a very active immune
system in 2 regards. First, the constant exposure would require the
immune system to be constantly working. It would always be under some
attack, as diseases evolve to counter the fish's defences. Secondly,
since the attack is progressive, the health of the fish depends on the
immune system's ability to produce the correct defence for when/if the
disease concentrations become higher.

In an aquarium, with our relatively huge fish-loads, disease
concentrations ramp up faster than their immune systems can react. Also
the immune system's ability to defend against a particular contagion
depends on if it was ever exposed to that contagion before, so (in
theory) a variety of low-level exposures, successfully defended against
would produce the strongest immune system. However, by intent, aquarium
bio-topes do the opposite, reducing the attacking contagions to zero.

In an established tank, with no introductions for say, one year, you
might conclude that the inhabitant's immune systems are dormant from lack
of use. This might be ideal (as it indicates a contagion-sterile
environment), unless you want to add something (fish, plant, snail etc).
Then you have the worst case scenario, a new contagion, small
environment, and a bunch of immune-suppressed fish who will not even know
what hit them.

NGS, New Germ Syndrome

There are varying defences for this, but I thought I'd start by floating
the concept through the newsgroups for comment first. There probably
exists a more technical term for this (especially as applied to humans),
so if you know of one which applies to fish, please share it.

NetMax

[Gordon]

"NetMax" > wrote in message
...
> There is NTS (new tank syndrome) which is well known to almost everyone,
> and there is OTS (old tank syndrome) which is known to most of the
> regular readers here and experienced hobbyists, but I think I have a new
> one for you to consider.
>
> Have you heard of this scenario before? You introduce a seemingly
> healthy fish to your tank (without quarantine, though I'm not certain how
> effective quarantine would be in this case), and within a few days, all
> the fish in the tank are dead (from bacteria and/or Ich). The common
> denominator is that the hobbyist had not added anything to that tank for
> a long time (over 8-9 months), and their fish were all healthy before.
> This is a real heart-breaker, and to add insult, very often, the
> introduced fish survives, seemingly oblivious to the carnage it has
> caused.
>
> Having heard of this occurrence from many other hobbyists (and
> experienced it), I've a hypothesis which I'll call NGS (new germ
> syndrome). I don't think it's as simple as the introduced fish being a
> carrier. The problem is the prolonged inactivity of the immune systems
> of fish which have been isolated for many months, preventing them from
> reacting to the almost benign germs which are always present in normal
> waterways. The human equivalent would be someone living in a sterile
> bubble for a long time, who would be at a pneumonia risk from common cold
> germs.
>
> The problem is worse with fish, as they don't have an atmospheric shield
> around them like humans. In nature, fish are all interconnected by
> water, which is an easy conductor for parasites, bacteria etc. If one
> fish is sick, they are all exposed to the same contagion, to varying
> degrees of concentration, depending on their proximity to the greatest
> source of the disease. Consequently, in nature, fish are always exposed
> to disease, and the exposure typically ramps up (as the disease spreads).
> This would require the fish (in nature) to have a very active immune
> system in 2 regards. First, the constant exposure would require the
> immune system to be constantly working. It would always be under some
> attack, as diseases evolve to counter the fish's defences. Secondly,
> since the attack is progressive, the health of the fish depends on the
> immune system's ability to produce the correct defence for when/if the
> disease concentrations become higher.
>
> In an aquarium, with our relatively huge fish-loads, disease
> concentrations ramp up faster than their immune systems can react. Also
> the immune system's ability to defend against a particular contagion
> depends on if it was ever exposed to that contagion before, so (in
> theory) a variety of low-level exposures, successfully defended against
> would produce the strongest immune system. However, by intent, aquarium
> bio-topes do the opposite, reducing the attacking contagions to zero.
>
> In an established tank, with no introductions for say, one year, you
> might conclude that the inhabitant's immune systems are dormant from lack
> of use. This might be ideal (as it indicates a contagion-sterile
> environment), unless you want to add something (fish, plant, snail etc).
> Then you have the worst case scenario, a new contagion, small
> environment, and a bunch of immune-suppressed fish who will not even know
> what hit them.
>
> NGS, New Germ Syndrome
>
> There are varying defences for this, but I thought I'd start by floating
> the concept through the newsgroups for comment first. There probably
> exists a more technical term for this (especially as applied to humans),
> so if you know of one which applies to fish, please share it.
>
> NetMax
>
>

NetMax,

Sounds reasonable to me. My wife and I have discussed many times a similiar
scenario with children. We have friends and family on both ends of the
scale. The scale being allowing one's kids to become exposed to any number
of things through the natural course of life, (playing the mud, eating
insects, contact with animals/other children etc.) thereby encouraging their
immune systems to be stronger. vs. Trying to bring your kids up in a
"vacumn" where everything is sterilised religiously and the kids are
prevented from coming into contact with diseases etc. such that when they
do, they fall ill easily and battle to overcome it. How many times have you
heard the story about how when a child first starts going to playschool,
within days or weeks they are sick and this continues for a few weeks until
their immune systems become stronger and they are able to cope with the bugs
they are coming into contact with. This is particularly evident where the
child is an only child and hasn't come into contact with many other kids,
prior to going to school. I digress......

It would seem to me that what you are talking about could also be worsened
by adopting too clinical an approach to tank maintenance. Recently there was
discussion in a post about how the soap on your hands could affect the fish
and the insinuation was that one shouldn't place your hands into the water
without being absolutely sure they are soap free. I don't disagree however
being too particular may actually be causing your fishes immune systems to
become "lazy." Similarly I have been given advise to have a seperate net for
each tank, in order to prevent the spread of disease from one tank to
another. Again I can see the logic in this, but on the other hand, unless
you are actually dealing with a disease, it would seem to me that the tiny
amount of pathogens which might be transferred by a net might actually
provide that "variety of low-level exposures" you mention.

We have all become familiar with the term immuno-suppression (sp?) which of
course is something slightly different, being a disease-like condition in
itself, but goes part-way to describe your new term "NGS." I did some
searching on Google and came up with the following article. It deal with
humans but the same must apply.

http://www.discoveryhealth.co.uk/general/g_story.asp?storyid=106923

Anyhow, just my thoughts!

Gordon

[Bob]

Supposedly if you run a uv sterilizer 24/7 you can have the same effect when
you do a water change if you have say...well water or something like that,
then the fish are supposed to get sick because they are not used to anything
in the water...

Then according to that, maybe a week in quarantine tank that is running a uv
sterilizer might have done the trick...ridding the new fish of pretty much
everything...or another way...was there a uv sterilizer on the tank that got
sick? maybe that would have prevented it?

Bob

[Bitey]

Uh, you might want to grab an immunology text and give it a thorough
cover-to-cover.

[Jim Morcombe]

I'd have to agree that this type of thing happens, although I feel that
quarantine would reduce the occurrences.

However, I don't believe that this is the only cause. I think there are
probably quite a number of different causes.

One cause I have found that is closely related to the Netmax Theory involves
fungus.

The fish I catch from the Moore River all bring some kind of fungus with
them, although they are completely uninfected and totally healthy.

In the river, the flowing water must prevent the fungus from getting a hold
on anything. However, in a small aquarium, the tiny traces that come with
the fish eventually grow and cause real problems.

Everytime I add a new fish into the aquarium fresh from the river, there
will be a fungal outbreak unless I dose it with something first.

Jim


NetMax > wrote in message
...
> There is NTS (new tank syndrome) which is well known to almost everyone,
> and there is OTS (old tank syndrome) which is known to most of the
> regular readers here and experienced hobbyists, but I think I have a new
> one for you to consider.
>
> Have you heard of this scenario before? You introduce a seemingly
> healthy fish to your tank (without quarantine, though I'm not certain how
> effective quarantine would be in this case), and within a few days, all
> the fish in the tank are dead (from bacteria and/or Ich). The common
> denominator is that the hobbyist had not added anything to that tank for
> a long time (over 8-9 months), and their fish were all healthy before.
> This is a real heart-breaker, and to add insult, very often, the
> introduced fish survives, seemingly oblivious to the carnage it has
> caused.
>
> Having heard of this occurrence from many other hobbyists (and
> experienced it), I've a hypothesis which I'll call NGS (new germ
> syndrome). I don't think it's as simple as the introduced fish being a
> carrier. The problem is the prolonged inactivity of the immune systems
> of fish which have been isolated for many months, preventing them from
> reacting to the almost benign germs which are always present in normal
> waterways. The human equivalent would be someone living in a sterile
> bubble for a long time, who would be at a pneumonia risk from common cold
> germs.
>
> The problem is worse with fish, as they don't have an atmospheric shield
> around them like humans. In nature, fish are all interconnected by
> water, which is an easy conductor for parasites, bacteria etc. If one
> fish is sick, they are all exposed to the same contagion, to varying
> degrees of concentration, depending on their proximity to the greatest
> source of the disease. Consequently, in nature, fish are always exposed
> to disease, and the exposure typically ramps up (as the disease spreads).
> This would require the fish (in nature) to have a very active immune
> system in 2 regards. First, the constant exposure would require the
> immune system to be constantly working. It would always be under some
> attack, as diseases evolve to counter the fish's defences. Secondly,
> since the attack is progressive, the health of the fish depends on the
> immune system's ability to produce the correct defence for when/if the
> disease concentrations become higher.
>
> In an aquarium, with our relatively huge fish-loads, disease
> concentrations ramp up faster than their immune systems can react. Also
> the immune system's ability to defend against a particular contagion
> depends on if it was ever exposed to that contagion before, so (in
> theory) a variety of low-level exposures, successfully defended against
> would produce the strongest immune system. However, by intent, aquarium
> bio-topes do the opposite, reducing the attacking contagions to zero.
>
> In an established tank, with no introductions for say, one year, you
> might conclude that the inhabitant's immune systems are dormant from lack
> of use. This might be ideal (as it indicates a contagion-sterile
> environment), unless you want to add something (fish, plant, snail etc).
> Then you have the worst case scenario, a new contagion, small
> environment, and a bunch of immune-suppressed fish who will not even know
> what hit them.
>
> NGS, New Germ Syndrome
>
> There are varying defences for this, but I thought I'd start by floating
> the concept through the newsgroups for comment first. There probably
> exists a more technical term for this (especially as applied to humans),
> so if you know of one which applies to fish, please share it.
>
> NetMax
>
>

[Dick]

If adjustment to tank environment makes old fish susceptable to new
fish disease, then shouldn't this also happen when I move my fish from
one tank to another such as to the quarantine tank? I have moved fish
that look poorly to my quarantine tank and the change helps them. I
assume the fish I keep in the quarantine tank to keep it cycled are
less crowded and less aggressive allowing the "new to the tank" fish
to relax and eat better. I had a runt clown loach that was looking
close to death recover and start eating when I moved him to the
quarantine tank. I keep him in the quarantine tank since he seems
happy there. I also move fish, for instance, if one male seems to be
picked on, fins nipped. I often move the weak fish to the quarantine
tank and move one fish from the quarantine tank to keep fish count
balanced.

Since each tank has been established on its own each environment will
be unique. I have never seen such moves detrimental, it almost always
resulted in the sick becoming well, with no problem for the home fish.




On Mon, 2 Feb 2004 14:20:04 +0800, "Jim Morcombe"
> wrote:

>I'd have to agree that this type of thing happens, although I feel that
>quarantine would reduce the occurrences.
>
>However, I don't believe that this is the only cause. I think there are
>probably quite a number of different causes.
>
>One cause I have found that is closely related to the Netmax Theory involves
>fungus.
>
>The fish I catch from the Moore River all bring some kind of fungus with
>them, although they are completely uninfected and totally healthy.
>
>In the river, the flowing water must prevent the fungus from getting a hold
>on anything. However, in a small aquarium, the tiny traces that come with
>the fish eventually grow and cause real problems.
>
>Everytime I add a new fish into the aquarium fresh from the river, there
>will be a fungal outbreak unless I dose it with something first.
>
>Jim
>
>
>NetMax > wrote in message
...
>> There is NTS (new tank syndrome) which is well known to almost everyone,
>> and there is OTS (old tank syndrome) which is known to most of the
>> regular readers here and experienced hobbyists, but I think I have a new
>> one for you to consider.
>>
>> Have you heard of this scenario before? You introduce a seemingly
>> healthy fish to your tank (without quarantine, though I'm not certain how
>> effective quarantine would be in this case), and within a few days, all
>> the fish in the tank are dead (from bacteria and/or Ich). The common
>> denominator is that the hobbyist had not added anything to that tank for
>> a long time (over 8-9 months), and their fish were all healthy before.
>> This is a real heart-breaker, and to add insult, very often, the
>> introduced fish survives, seemingly oblivious to the carnage it has
>> caused.
>>
>> Having heard of this occurrence from many other hobbyists (and
>> experienced it), I've a hypothesis which I'll call NGS (new germ
>> syndrome). I don't think it's as simple as the introduced fish being a
>> carrier. The problem is the prolonged inactivity of the immune systems
>> of fish which have been isolated for many months, preventing them from
>> reacting to the almost benign germs which are always present in normal
>> waterways. The human equivalent would be someone living in a sterile
>> bubble for a long time, who would be at a pneumonia risk from common cold
>> germs.
>>
>> The problem is worse with fish, as they don't have an atmospheric shield
>> around them like humans. In nature, fish are all interconnected by
>> water, which is an easy conductor for parasites, bacteria etc. If one
>> fish is sick, they are all exposed to the same contagion, to varying
>> degrees of concentration, depending on their proximity to the greatest
>> source of the disease. Consequently, in nature, fish are always exposed
>> to disease, and the exposure typically ramps up (as the disease spreads).
>> This would require the fish (in nature) to have a very active immune
>> system in 2 regards. First, the constant exposure would require the
>> immune system to be constantly working. It would always be under some
>> attack, as diseases evolve to counter the fish's defences. Secondly,
>> since the attack is progressive, the health of the fish depends on the
>> immune system's ability to produce the correct defence for when/if the
>> disease concentrations become higher.
>>
>> In an aquarium, with our relatively huge fish-loads, disease
>> concentrations ramp up faster than their immune systems can react. Also
>> the immune system's ability to defend against a particular contagion
>> depends on if it was ever exposed to that contagion before, so (in
>> theory) a variety of low-level exposures, successfully defended against
>> would produce the strongest immune system. However, by intent, aquarium
>> bio-topes do the opposite, reducing the attacking contagions to zero.
>>
>> In an established tank, with no introductions for say, one year, you
>> might conclude that the inhabitant's immune systems are dormant from lack
>> of use. This might be ideal (as it indicates a contagion-sterile
>> environment), unless you want to add something (fish, plant, snail etc).
>> Then you have the worst case scenario, a new contagion, small
>> environment, and a bunch of immune-suppressed fish who will not even know
>> what hit them.
>>
>> NGS, New Germ Syndrome
>>
>> There are varying defences for this, but I thought I'd start by floating
>> the concept through the newsgroups for comment first. There probably
>> exists a more technical term for this (especially as applied to humans),
>> so if you know of one which applies to fish, please share it.
>>
>> NetMax
>>
>>
>

[Bitey]

On Mon, 02 Feb 2004 05:03:34 -0600, Dick >
wrote:

>If adjustment to tank environment makes old fish susceptable to new
>fish disease, then shouldn't this also happen when I move my fish from
>one tank to another such as to the quarantine tank? I have moved fish
>that look poorly to my quarantine tank and the change helps them. I
>assume the fish I keep in the quarantine tank to keep it cycled are
>less crowded and less aggressive allowing the "new to the tank" fish
>to relax and eat better. I had a runt clown loach that was looking
>close to death recover and start eating when I moved him to the
>quarantine tank. I keep him in the quarantine tank since he seems
>happy there. I also move fish, for instance, if one male seems to be
>picked on, fins nipped. I often move the weak fish to the quarantine
>tank and move one fish from the quarantine tank to keep fish count
>balanced.

The theory is bogus because it assumes that the innate immune system
of vertebrates does not exist.

Did your clown look like this:

http://www.geocities.com/pktechlizard/skinny.htm ?

Very common these days, especially in very young specimens.

[NetMax]

"Bitey" > wrote in message
...
> Uh, you might want to grab an immunology text and give it a thorough
> cover-to-cover.

You can probably tell that I've never read an immunology text before ;~).
Would you care to elaborate on your statement:
"The theory is bogus because it assumes that the innate immune system of
vertebrates does not exist."
thanks!
NetMax

[NetMax]

"Dick" > wrote in message
...
> If adjustment to tank environment makes old fish susceptable to new
> fish disease, then shouldn't this also happen when I move my fish from
> one tank to another such as to the quarantine tank? I have moved fish
> that look poorly to my quarantine tank and the change helps them. I
> assume the fish I keep in the quarantine tank to keep it cycled are
> less crowded and less aggressive allowing the "new to the tank" fish
> to relax and eat better. I had a runt clown loach that was looking
> close to death recover and start eating when I moved him to the
> quarantine tank. I keep him in the quarantine tank since he seems
> happy there. I also move fish, for instance, if one male seems to be
> picked on, fins nipped. I often move the weak fish to the quarantine
> tank and move one fish from the quarantine tank to keep fish count
> balanced.

I don't think your example is applicable (if I understand you correctly).
The risk is when isolated fish are exposed to pathogens. All your tanks
would probably have the same diseases (or lack off) unless you practiced
isolation procedures (a net and algae scrub for each tank, and never
moving things between them). All your tank's water parameters will also
probably be idential (pH, gH and kH) making tank transfers easy.

NetMax

> Since each tank has been established on its own each environment will
> be unique. I have never seen such moves detrimental, it almost always
> resulted in the sick becoming well, with no problem for the home fish.

<snip>

[NetMax]

Another interesting thing about fungus (I've been told) is that it is
naturally occurring and rarely completely eradicated. I suppose that in
a closed environment like an aquarium, the species of fungus would be
static, so the fish would acclimate to them. Fungus is rarely a problem
to fish though (except for open wounds). I wonder if it isn't bacterial
in origin? Thanks for sharing.

NetMax

"Jim Morcombe" > wrote in message
...
> I'd have to agree that this type of thing happens, although I feel that
> quarantine would reduce the occurrences.
>
> However, I don't believe that this is the only cause. I think there
are
> probably quite a number of different causes.
>
> One cause I have found that is closely related to the Netmax Theory
involves
> fungus.
>
> The fish I catch from the Moore River all bring some kind of fungus
with
> them, although they are completely uninfected and totally healthy.
>
> In the river, the flowing water must prevent the fungus from getting a
hold
> on anything. However, in a small aquarium, the tiny traces that come
with
> the fish eventually grow and cause real problems.
>
> Everytime I add a new fish into the aquarium fresh from the river,
there
> will be a fungal outbreak unless I dose it with something first.
>
> Jim
<snip>

[NetMax]

"Bob" > wrote in message
...
> Supposedly if you run a uv sterilizer 24/7 you can have the same effect
when
> you do a water change if you have say...well water or something like
that,
> then the fish are supposed to get sick because they are not used to
anything
> in the water...
>
> Then according to that, maybe a week in quarantine tank that is running
a uv
> sterilizer might have done the trick...ridding the new fish of pretty
much
> everything...or another way...was there a uv sterilizer on the tank
that got
> sick? maybe that would have prevented it?
>
> Bob

I've never looked into the effects of continuous UV operation on fish
health. A UV on the quarantine tank sounds like a logical precaution.
Probably better than continuously adding low-level pathogens ;~)

NetMax

[coelacanth]

"Bitey" > wrote in message
...
> Uh, you might want to grab an immunology text and give it a thorough
> cover-to-cover.

Are there any good ones which cover fish immunology? The ones
I've seen mostly seem to have been written in the middle ages
(i.e. before the discovery of PCR).

-coelacanth

[coelacanth]

"Bitey" > wrote in message
...
> On Mon, 02 Feb 2004 05:03:34 -0600, Dick >
> wrote:
>
> The theory is bogus because it assumes that the innate immune system
> of vertebrates does not exist.
>
> Did your clown look like this:
>
> http://www.geocities.com/pktechlizard/skinny.htm ?
>
> Very common these days, especially in very young specimens.

The theory is not even vaguely bogus. Stress results in the release of
corticosteroids which are known to suppress many immunological
functions, both innate and acquired. Moving a fish which is trying
to encapsulate mycobacterium with macrophages (or whatever
fish do with tubercular bacteria) to a calmer environment where
it gets its share of food without a struggle could definitely affect
the outcome of such an infection IMHO.

On the point of NetMax's original posting, I can easily envision
a scenario where a fish is chronically infected with a low level
pathogen and has developed a secondary or tertiary cellular
response to it. (sorry to be a bit vague, but I don't recall if fish
have B/T cells or something more basic and I'm too lazy to go
dig up "Fundamental Immunology" right now). The resident
fish are infected and have ONLY their innate immunity and
whatever primary response for protection. In mammals--
well mice and men, anyway--it takes 2-3 weeks to go from
a rough IgM response to a more finely tuned IgG response.
I'd guess the response in fish is slower. I'd also argue that
Max's NGS results from a fish with a low-level chronic infection
being placed into a closed system and shedding pathogens which
can multiply rapidly in the other fish and kill them while not
altering their minimal impact on the host.

As an aside, this would argue that quarantine is not a perfect
preventative measure. A fish with really low-level infection
would still be infectious. The best defense would be a very
healthy innate immune system in all the resident fish and I'd
guess that many case of NGS are really the result of lowered
levels of slime and other deficits in the immunity of the "old"
fish. Come to think of it, age could be a factor too...

-coelacanth

[Dick]

On Tue, 03 Feb 2004 01:42:02 GMT, Bitey >
wrote:

>On Mon, 02 Feb 2004 05:03:34 -0600, Dick >
>wrote:
>
>>If adjustment to tank environment makes old fish susceptable to new
>>fish disease, then shouldn't this also happen when I move my fish from
>>one tank to another such as to the quarantine tank? I have moved fish
>>that look poorly to my quarantine tank and the change helps them. I
>>assume the fish I keep in the quarantine tank to keep it cycled are
>>less crowded and less aggressive allowing the "new to the tank" fish
>>to relax and eat better. I had a runt clown loach that was looking
>>close to death recover and start eating when I moved him to the
>>quarantine tank. I keep him in the quarantine tank since he seems
>>happy there. I also move fish, for instance, if one male seems to be
>>picked on, fins nipped. I often move the weak fish to the quarantine
>>tank and move one fish from the quarantine tank to keep fish count
>>balanced.
>
>The theory is bogus because it assumes that the innate immune system
>of vertebrates does not exist.
>
>Did your clown look like this:
>
>http://www.geocities.com/pktechlizard/skinny.htm ?
>
>Very common these days, especially in very young specimens.

Sort of, but not so drawn in. I mostly noticed an eating problem. He
wasn't aggressive and also couldn't seem to bite the flakes. He would
get smaller pieces of flake. He seemed to have trouble opening his
mouth far enough.

After transfer to the quarantine tank, he was eating, small pieces to
begin, but as he gained strength he became much more aggressive and
could take bites from larger flakes. He has filled out some, but is
still a runt. He seems quite content to share the tank with about 9
mollies.

[Dr Engelbert Buxbaum]

NetMax wrote:


> Having heard of this occurrence from many other hobbyists (and
> experienced it), I've a hypothesis which I'll call NGS (new germ
> syndrome). I don't think it's as simple as the introduced fish being a
> carrier. The problem is the prolonged inactivity of the immune systems
> of fish which have been isolated for many months, preventing them from
> reacting to the almost benign germs which are always present in normal
> waterways. The human equivalent would be someone living in a sterile
> bubble for a long time, who would be at a pneumonia risk from common cold
> germs.

> In an aquarium, with our relatively huge fish-loads, disease
> concentrations ramp up faster than their immune systems can react. Also
> the immune system's ability to defend against a particular contagion
> depends on if it was ever exposed to that contagion before, so (in
> theory) a variety of low-level exposures, successfully defended against
> would produce the strongest immune system. However, by intent, aquarium
> bio-topes do the opposite, reducing the attacking contagions to zero.


Several problems come to mind:

a) Species-dependent susceptibility to pathogens: Some species can
harbour certain microorganisms without apparent ill-effect, which cause
overt disease in other species.

b) Mixing of pathogenes: If a pathogen (especially virus) jumps to a
different species, it may mix its genetic material with pathogens
already present in that species, effectively creating a new pathogen
agains which the defences of the host are ineffective. The human
equivalent of this would be the great flu pandemics in the 20th century
(mixing of bird and pig with human influenza viruses).

c) Fishes exposed to a pathogen will either survive the infection or die
from it. If they survive, they may still harbour the pathogen but
without overt symptoms. The molecular cause is heterogeneity in the
major histocompatibility complex (MHC), a key protein in the immune
system. Some individuals are more susceptible to a disease than others,
if a population is exposed to a pathogen, resistant genotypes will
enrich in that population, which may make that population more
susceptible to other diseases.

If that happens in the tank of one breader, the surviving fishes from
that dealer may all harbour the infection. If brought into contact with
fishes from a different source, which had not been exposed previously, a
severe outbreak may result.

d) The unnaturally high density of fishes in a tank (even if the usual 1
cm per 2 l rule is followed) makes contagion easier and certainly
decreases the effectiveness of the fish's immune system.


A partial solution is the use of medicated food during the quarantaine
periode, or during the first week after mixing the fishes. I had
considerable success with that method in preventing the effect described
by you.

[Robert Flory]

"NetMax" > wrote in message
...
SNIP....

> In an aquarium, with our relatively huge fish-loads, disease
> concentrations ramp up faster than their immune systems can react. Also
> the immune system's ability to defend against a particular contagion
> depends on if it was ever exposed to that contagion before, so (in
> theory) a variety of low-level exposures, successfully defended against
> would produce the strongest immune system. However, by intent, aquarium
> bio-topes do the opposite, reducing the attacking contagions to zero.
>
> In an established tank, with no introductions for say, one year, you
> might conclude that the inhabitant's immune systems are dormant from lack
> of use. This might be ideal (as it indicates a contagion-sterile
> environment), unless you want to add something (fish, plant, snail etc).
> Then you have the worst case scenario, a new contagion, small
> environment, and a bunch of immune-suppressed fish who will not even know
> what hit them.
>
> NGS, New Germ Syndrome
>
> There are varying defences for this, but I thought I'd start by floating
> the concept through the newsgroups for comment first. There probably
> exists a more technical term for this (especially as applied to humans),
> so if you know of one which applies to fish, please share it.
>
> NetMax
>
NetMax,

Being a geologist not a biologist, I'd hate to name a cause... However...

When I was I Grad school I spent some time in Antarctica. I was always
healthy in the field but when I was back at the base, it seemed like every
weekly flight brought a fresh respiratory crud the quickly made the rounds
of the base then cleared up. We'd all bet healthy till the next trip.

People used to blame it on "exotic" bus from New Zealand, however I never
picked up anything going and coming through New Zealand. I naver found Kiwi
bugs to be exotic. Must say that after 3 months bunking with a smelly field
assistant, the ladies were quite something. Always bettr looking on the way
back than they were on the trip down ;-)
Bobn

[NetMax]

"Robert Flory" > wrote in message
...
>
> "NetMax" > wrote in message
> ...
> SNIP....
>
> > In an aquarium, with our relatively huge fish-loads, disease
> > concentrations ramp up faster than their immune systems can react.
Also
> > the immune system's ability to defend against a particular contagion
> > depends on if it was ever exposed to that contagion before, so (in
> > theory) a variety of low-level exposures, successfully defended
against
> > would produce the strongest immune system. However, by intent,
aquarium
> > bio-topes do the opposite, reducing the attacking contagions to zero.
> >
> > In an established tank, with no introductions for say, one year, you
> > might conclude that the inhabitant's immune systems are dormant from
lack
> > of use. This might be ideal (as it indicates a contagion-sterile
> > environment), unless you want to add something (fish, plant, snail
etc).
> > Then you have the worst case scenario, a new contagion, small
> > environment, and a bunch of immune-suppressed fish who will not even
know
> > what hit them.
> >
> > NGS, New Germ Syndrome
> >
> > There are varying defences for this, but I thought I'd start by
floating
> > the concept through the newsgroups for comment first. There probably
> > exists a more technical term for this (especially as applied to
humans),
> > so if you know of one which applies to fish, please share it.
> >
> > NetMax
> >
> NetMax,
>
> Being a geologist not a biologist, I'd hate to name a cause...
However...
>
> When I was I Grad school I spent some time in Antarctica. I was
always
> healthy in the field but when I was back at the base, it seemed like
every
> weekly flight brought a fresh respiratory crud the quickly made the
rounds
> of the base then cleared up. We'd all bet healthy till the next trip.
>
> People used to blame it on "exotic" bus from New Zealand, however I
never
> picked up anything going and coming through New Zealand. I naver found
Kiwi
> bugs to be exotic. Must say that after 3 months bunking with a smelly
field
> assistant, the ladies were quite something. Always bettr looking on
the way
> back than they were on the trip down ;-)
> Bobn

Not sure what it all means, but ROTFLMAO :o)

NetMax

[Dick]

n Sat, 7 Feb 2004 16:25:19 -0800, "Robert Flory" >
wrote:

>
>"NetMax" > wrote in message
...
>SNIP....
>
>> In an aquarium, with our relatively huge fish-loads, disease
>> concentrations ramp up faster than their immune systems can react. Also
>> the immune system's ability to defend against a particular contagion
>> depends on if it was ever exposed to that contagion before, so (in
>> theory) a variety of low-level exposures, successfully defended against
>> would produce the strongest immune system. However, by intent, aquarium
>> bio-topes do the opposite, reducing the attacking contagions to zero.
>>
>> In an established tank, with no introductions for say, one year, you
>> might conclude that the inhabitant's immune systems are dormant from lack
>> of use. This might be ideal (as it indicates a contagion-sterile
>> environment), unless you want to add something (fish, plant, snail etc).
>> Then you have the worst case scenario, a new contagion, small
>> environment, and a bunch of immune-suppressed fish who will not even know
>> what hit them.
>>
>> NGS, New Germ Syndrome
>>
>> There are varying defences for this, but I thought I'd start by floating
>> the concept through the newsgroups for comment first. There probably
>> exists a more technical term for this (especially as applied to humans),
>> so if you know of one which applies to fish, please share it.
>>
>> NetMax
>>
>NetMax,
>
>Being a geologist not a biologist, I'd hate to name a cause... However...
>
>When I was I Grad school I spent some time in Antarctica. I was always
>healthy in the field but when I was back at the base, it seemed like every
>weekly flight brought a fresh respiratory crud the quickly made the rounds
>of the base then cleared up. We'd all bet healthy till the next trip.
>
>People used to blame it on "exotic" bus from New Zealand, however I never
>picked up anything going and coming through New Zealand. I naver found Kiwi
>bugs to be exotic. Must say that after 3 months bunking with a smelly field
>assistant, the ladies were quite something. Always bettr looking on the way
>back than they were on the trip down ;-)
>Bobn
>

De je vu, I recall reading, many, many years ago of a polar lab that
noticed the same thing. New people coming in with colds, and the old
timers getting it. No new arrivals, no illness.

As an experiment, they isolated the new comers the first week and no
illness transfer. As I recall, they finally narrowed it down to a
respiratory problem. Newcomers were given masks and iodine treated
tissues. This allowed them to mingle from the start.

[NetMax]

"Dick" > wrote in message
...
> n Sat, 7 Feb 2004 16:25:19 -0800, "Robert Flory" >
> wrote:
>
> >
> >"NetMax" > wrote in message
> ...
> >SNIP....
> >
> >> In an aquarium, with our relatively huge fish-loads, disease
> >> concentrations ramp up faster than their immune systems can react.
Also
> >> the immune system's ability to defend against a particular contagion
> >> depends on if it was ever exposed to that contagion before, so (in
> >> theory) a variety of low-level exposures, successfully defended
against
> >> would produce the strongest immune system. However, by intent,
aquarium
> >> bio-topes do the opposite, reducing the attacking contagions to
zero.
> >>
> >> In an established tank, with no introductions for say, one year, you
> >> might conclude that the inhabitant's immune systems are dormant from
lack
> >> of use. This might be ideal (as it indicates a contagion-sterile
> >> environment), unless you want to add something (fish, plant, snail
etc).
> >> Then you have the worst case scenario, a new contagion, small
> >> environment, and a bunch of immune-suppressed fish who will not even
know
> >> what hit them.
> >>
> >> NGS, New Germ Syndrome
> >>
> >> There are varying defences for this, but I thought I'd start by
floating
> >> the concept through the newsgroups for comment first. There
probably
> >> exists a more technical term for this (especially as applied to
humans),
> >> so if you know of one which applies to fish, please share it.
> >>
> >> NetMax
> >>
> >NetMax,
> >
> >Being a geologist not a biologist, I'd hate to name a cause...
However...
> >
> >When I was I Grad school I spent some time in Antarctica. I was
always
> >healthy in the field but when I was back at the base, it seemed like
every
> >weekly flight brought a fresh respiratory crud the quickly made the
rounds
> >of the base then cleared up. We'd all bet healthy till the next trip.
> >
> >People used to blame it on "exotic" bus from New Zealand, however I
never
> >picked up anything going and coming through New Zealand. I naver found
Kiwi
> >bugs to be exotic. Must say that after 3 months bunking with a smelly
field
> >assistant, the ladies were quite something. Always bettr looking on
the way
> >back than they were on the trip down ;-)
> >Bobn
> >
>
> De je vu, I recall reading, many, many years ago of a polar lab that
> noticed the same thing. New people coming in with colds, and the old
> timers getting it. No new arrivals, no illness.
>
> As an experiment, they isolated the new comers the first week and no
> illness transfer. As I recall, they finally narrowed it down to a
> respiratory problem. Newcomers were given masks and iodine treated
> tissues. This allowed them to mingle from the start.

Just had this image of fish swimming around with surgical masks ;~)

I've installed a 16W UV light on a tank at work and will be doing some
tests to assess its value in this regard. I'll keep you posted.

NetMax