Koi Herpes Virus 2005
Koi Herpes Virus is a common virus of Koi
which attacks the surfaces of the fish. This includes
the surface of the skin, the surface of the gills and
the surface-linings of the fishes' kidney. It doesn't
It spreads from fish to fish very rapidly
and kills most of its victims in a few short days. In
water which is about seventy five degrees Fahrenheit,
Koi Herpes Virus will kill 90% of affected fish in a mere
four to six days. The virus does not "hide" in fish unless
the fish is naturally immune or unless the fish is in
water which is cold, under sixty five degrees Fahrenheit.
If the fish is susceptible to KHV it will show symptoms
and be sick if the water temperature is in the mid to
If you raise the water temperature to an extremely
warm temperature, the virus dies in the fish. This is
not unheard of among viruses because they are actually
unstable pieces of DNA which require cell contents and
an optimal temperature range to live. What is unique is
that many Herpes viruses affect warm blooded animals you cannot materially change the body temperature of a
warm blooded animal. The fact that we can heat up a cold
blooded fish to temperatures which would be considered
extreme by their own natural history is an asset in the
control of symptoms referable to KHV in Koi.
So, many people are aware that heating Koi
at a rate of ONE degree Fahrenheit per hour until the
affected fish are in water which is at 86 Degrees Fahrenheit
will control the mortalities [deaths] among KHV fish.
It is imperative that when you warm up KHV infected fish
that you control co-morbidities and increase aeration
to the point of overkill. Detailed documents exist at
"www.koivet.com" about how to accomplish this and how
to control co-infections.
After heating up a group of fish and saving
them from Koi Herpes Virus, are they safe from re-infection
and can they cause infection in other fishNeither answer
Koi which are heated and saved from Koi Herpes
Virus are usually susceptible to re-infection because
it takes up to thirty days of exposure to create antibodies
in Koi. If the fish are heated early in their infection,
the virus will not have been present in the Koi bloodstream
long enough to make them immune. After successful heating,
there are NO cases wherein closed collections of fish
were re-infected by "carriers" left behind by heating.
Always, new infected fish are introduced to these collections.
All of these notes are anecdotal, meaning they were not
validated by scientific measurement.
Therefore, all heated "survivors" SHOULD BE
CONSIDERED INFECTED AND INFECTIOUS until proven otherwise.
Since most people who suffer through a KHV
outbreak have survivors, and since there are many of us,
the dilemma then is: "Should I get new fish and put them
in with my KHV survivors"
Many people have mixed new fish with KHV survivors
without sacrifice. And there have been no infections from
the survivors but the statistical group is small and there
have been no controlled studies. Other people have killed
all their KHV survivors, and for some retailers this has
meant the death of hundreds if not thousands of fish,
needlessly; but there is a better way.
Quite a few people are willing to provide
homes for KHV survivors. Individuals like Brenda and Charlie
Atwell, John Smoak, Ed O'Day, Erik Johnson and others
will pay shipping on otherwise free, eligible fish to
add them to their collections of KHV survivors. These
fish are all given a "second chance". All these fish,
added to collections of KHV survivors, contribute to our
understanding of the latency of the virus.
To qualify your KHV survivors for placement
in our informal "Post-KHV Adoption Program" please contact
Ed O'Day or John Smoak.
John Smoak: firstname.lastname@example.org
Ed O'Day email@example.com
Additional Notes and Common Questions:
Starting over (options):
What to do with remaining fishRemaining
fish should either be destroyed humanely, usually by anesthetic
overdose then freezing. Alternatively, there are many
people with small collections of KHV survivors who would
add your fish to their collections, having already been
through KHV and not fearing a relapse if they have engineered
heating systems. One of the problems with eliminating
all your survivors and buying all new fish is that you
have a ten percent chance of buying NEW fish with KHV
infections, so there's no guarantee that you can restock
without returning to square-one again.
What to do with your pond The virus is VERY
unstable outside the fish. If the pond is left without
ANY fish host for 3 days, the virus is considered by most
experts to be "gone". If you're not one to take any chances,
double dose Chloramine T or double dose Potassium can
be deployed in a fishless ecosystem and the virus will
not survive it. Clorox at a dilution of 1:30 is MORE than
enough to sterilize the virus from a contaminated retail
How long to wait for new fish Since (odds
against you) any new fish you buy theoretically have a
ten percent chance of being infected with KHV (especially
if they are from Taiwan, Thailand, Malaysia or Sri Lanka,
and (odds for you) since the virus is not likely to last
long in the pond ecosystem without a fish host, a week
"without fish" would be a safe recommendation, plus or
minus the additional safety net of the sterilization techniques
Locate a "KHV Survivor" rescue pond If you
are interested in placement of your fish with good-hearted
collectors of Koi who have survived KHV, please contact:
John Smoak: firstname.lastname@example.org Ed O'Day email@example.com