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Over Dosing is better than Under Dosing but No Dosing is the best !
At
one point or another, disease is going to appear and perhaps
even spread in your tank. It may start by infecting just one
fish or as an epidemic situation where more fish have the same
disease. Then you open your books (I assume you have at least one
book on fish diseases), ask your local pet shop guy (who sells you
tons of "high-tech" medications) or E-mail the disease
guru you know to seek advice. The answer will most probably be the
same, and it usually reads like that : "Your fish has probably
got the x disease which means you should isolate it and treat it
with the z medication". So far so good. At least you have an
answer and the next step is to follow the guru's suggestion :
isolate the fish and treat it with a suitable medication.
Firstly,
in some cases, the reasoning for isolating the fish is
questionable. If the fish is heavily infected with external micro
organisms then, most probably, other fishes are infected too, or the
micro organism is present in the water column. It is common sense
that the micro organism was present in the water and this is how the
fish was infected--so probably it is still in the water, too. An
exception is when the infected fish is a new addition which was not
quarantined - the only difference being that the micro organism was
not present before the infection but was introduced by you. It
sounds reasonable to assume that, in this case, treating the
whole of the tank is preferable (unless you have as many hospital
tanks as fishes). I will use the term "micro organisms" in
the broad sense i.e. it shall include fungi,
bacteria, protozoa and viruses.
To
start with, there is nothing
you can do for viral
infections. Viruses are a
special king of micro organism which, simply put, is at the
borderline of life. These very tiny micro organisms have the ability
to transform and adapt easily and even "die" if they need
to. Of course, they do not die. What they do is they transform in a
new stage which is very resistant while there are no signs of life
as we know it. They do not breath, they don't metabolise, move or
reproduce at this stage. Needless to say, there is simply no
medication that works (not even for humans, with notable
exceptions). When you deal with a viral infection you have to rely
on the good condition of the immune system of your fish. That is
another good reason to keep them in prime shape and this is why
stressed fish is always prone to viral infections. In this case, you
may see you fish being lazy, refraining from eating or lying on the
bottom for a couple of days and then behave normally again. Now we
have covered the exception. Needless to say, for us, the hobbyists,
there is no way to discriminate between a viral infection and an
internal bacterial infection so the point I made was mostly
academic. Only a post-mortem section, performed by a specialist
might reveal the true cause of death. If you have a tank full of
really expensive species perhaps this is what you should do. Bear in
mind that viral infections will usually spread, so you have to take
advantage of the time it will take the virus to reproduce. Of
course, all you can do is isolate your fishes (one in each tank) and
hope that you were quick enough. What we normally do is take note of
the signs, guess what the disease is (the serious keeper may even
read a couple of books, surf the net or seek professional advice)
and use the right medication at once. Of course, the
"right" medication may not be right at all, but you don't
know it, do you? On top of that, if the situation looks hopeless,
doing something is better than doing nothing, which is exactly the
theory most of us usually follow.
We
now assume that we use a given medication and we have correctly
identified the infection to be a bacterial (or fungal or protozoan)
one. Firstly, we should read what the package insert says. There is
a reason they put these leaflets in the boxes you know. The reason
is for us to read them. And they want us to read them because they
include some very useful information on that piece of paper. So take
the time to read it carefully. Take all the precautions /
preparatory steps suggested. Make sure this medication is meant to
treat the disease you are trying to treat. If you note sentences
including "may treat some cases of" or "occasionally
potent" followed by the disease's name, forget it. Always keep
in mind that the narrower the spectrum of a medication the more
potent it usually is. All around players usually give you an average
efficacy all around. When preparing disinfectants (meant to treat
surfaces or tools) companies may include very potent active
ingredients that will kill any pathogen within seconds. Since these
ingredients will also kill a fish (or even a human) within seconds
they can't be used in medications. So, when a preparation is to be
used on living organisms it must contain substances that can act on
the pathogen while not harming the hosting organism. This, of course
calls for more specialized products, which need some conditions in
order to act the way they should. The reason for this is that the
medication must be present in concentrations within the therapeutic
range.
What
is that? If we assume that the pathogen is killed at
concentration x while the fish is killed at concentration 5x then
the therapeutic range of this medication is between x and 5x. Very
clear and I am sure it makes sense. The key point here is that the
medication's concentration must be over x and definitely below 5x.
The precautions stated in the insert give you the conditions under
which what you add in your tank is what will work. This assumes that
you have already created the right conditions for this medication.
Thus you should immediately remove activated carbon if it says so.
Increase aeration if so advised (increase it anyway I would say,
unless otherwise stated). Raise the temperature if needed. Do not
add chlorine removers if so stated. Better still, perform a large
water change before adding the medication (in order to remove as
much of the conditioner as possible). Pay special attention to the
"small letters". In some medications you have to remove
ammonia removers, or salt. Some medications may affect your water
parameters so you may need to compensate for that. I was nastily
surprised when I used a "peroxide releasing" product,
which lowered the pH of my tank from 8,4 to 7,0 in an hour. Turn off
the lights of your tank for the whole course of the treatment if the
medication is light sensitive (example : tetracycline). If direct or
indirect sunlight reaches your tank, cover it with a towel or
blanket. Follow these rules. If you don't you are simply
under-dosing. Under
dosing means that the actual concentration of the medication in your
water is lower than the minimum lethal concentration recommended for
that particular micro organism or, the duration of exposure is
shorter than the minimum lethal exposure.
In both cases you have - or you may have - a very serious problem.
The same is true when you calculate the volume of your tank. Instead
of guestimating how many litres your rocks occupy, take my advice :
ignore the rocks. Treat the tank as if it was full of water. This is
over-dosing.
I am sure that you can reverse the definition for under-dose.
In
some cases, the medication calls for two doses per day. For some
reason you forget a dose and you only remember it next day.
Unfortunately, you under
dosed
again. Well, yes, you under-dosed, so what?? Let's see
what…
Micro
organisms that have a life cycle lasting a week or more cause
some diseases and this should be taken into consideration. In some
cases the micro organism is only vulnerable during one stage of this
cycle while being resistant to medication during the others (e.g.
formation of resistant cysts or bacteria spores).
Continued
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