How does it work?
And what are the dangers in using it?
By Jim E. Quarles
Jan 10 2000
If you keep discus I am sure sooner or later you will hear about a
product called Potassium Permanganate or just P.P.
And the purpose of this article is to make it perfectly clear how pp
works when used as a fish medication, and the dangers of using it without
proper controls and understanding of what it does and how it does it.
MAKE NO MISTAKE potassium permanganate is a DANGEROUS SUBSTANCE.
(Kmn04) It is ineffective in the presence of organic matter.
It is corrosive. And it is not a spirochaetal agent. It can be
explosive. And it is a toxic compound.
Now with that said, how does it work used as a bactericide? Just what
are it's physical and chemical reactions with organic matter namely in
this case the external surface of a fish and any bacteria and or parasites
that might be found in its environment?
Potassium Permanganate is a very strong oxygenizing agent. It's effect
upon organic matter is to oxidizes it, ( if effect burn it up). It removes
and breaks down organic tissue. The effect is chemically different, but
you could compare it to using fire to burn up any organic matter that
comes into contact with it.
When used on discus the first thing that occurs is that the slime coat
is attacked and oxidized. Once that protective coating is gone, if the
solution is strong enough it will then start to oxidize the finer tissues
exposed to it. The gill membranes and finer fin areas are next acted upon.
If the mis-use has gone this far, the fish is doomed in any event. But
next the tissue that the pp starts to oxidized is the epithelial membrane
or the epithelium of the gills.
If this stage is reached you have in effect fried the external body of
the fish to a point it will not survive. But far short of that damage, if
in deed that has happened, the usefulness of the fish has been greatly
reduced, and more than likely caused it to suffer a good deal if it lives.
The natural defenses of the discus includes the mucus layer that covers
the exterior surfaces of the fish, this mucus is a moving layer of
protection against parasites and bacteria. By peristaltic action the mucus
is moved from head to tail and then shed into the water to be replaced by
renewed mucus. Parasites and bacteria must get past this layer in order to
infect the fish. Under normal conditions most if not all the parasitic
agents are caught in this mucus layer and expelled from the fish's body.
Now along comes the hobbyist, and mixes up some good old, Potassium
Permanganate, and in some concentration or other dumps it into the tank.
Now if the object of this exercise is to burn off the mucus layer of the
fish or greatly reduce it, that's fine, because that is exactly what is
going to happen.
This can be a useful event in very rare cases of massive attacks by
parasites on the mucus, such as is the case with Discus Plague. In the
case of plague you want to strip the mucus layer and let the fish resupply
a fresh coat, thereby removing a high concentration of infectious agents.
The treatment is followed by placing the treated fish in new fresh
parasite free water.
SO WHAT EFFECT DOES PP HAVE ON
ANY PARASITE PRESENT?
To some extent it has the same effect on a pathogen that it has on the
mucus layer of the fish. But it should be remembered that most parasites
have their own defenses against attack, that allows them to survive and
complete their own life cycle. The number one defense is to encapsulate
when attacked by any agent. Once the parasite has become encapsulated its
defenses are far stronger and harder to penetrate or oxidize then the
epithelial membrane of the fish. Also, when some parasites encapsulate
they embed themselves in the membranes of the host. So that if you are
able to remove even a large number of parasites, you may be setting up
conditions of later infections when the encapsulated parasite once again
A general condition that is best remembered is that using any chemical
it is easier to kill or damage the host long before you can cause the
total removal of a parasite.
So Should you Ever Use
The answer to that is a qualified yes! I can think of two reasons and
conditions under which the use of pp maybe justified.
- If and when you wish to remove the mucus layer of the fish.
- As a pre-conditioner of water to be used in an aquarium system.
I have already explained how the pp oxidizes and causes the loss of the
mucus layer of a fish.
But what about choice # 2. Preconditioning water for aquarium use? How
do you do that and why?
Used in the right concentration pp will oxidize all organic matter it
comes into contact with. So you can see that if used in holding water,
later to be used in fish tanks, any parasite or bacteria will be burned
away or killed other than those who are able to encapsulate under those
The only problem with this is that the mixture must be such that the pp
becomes inert once all organic substances are removed. This is a complex
problem and at best guess work unless the color of the water turns a very
light brown or you have a test kit that allows you to measure any
remaining pp that is active as a oxidizer.
The point being made here other than to explain how pp works and why it
works is to point out it is not a cure all for everything that you see and
think are effecting the health of your discus.
THINK OF POTASSIUM PERMANGANATE AS A TREATMENT
OF LAST RESORT NOT AS A WATER CONDITIONER OR CURE ALL.