ein Bericht von Erik Johnson
More on Heating KHV – by Erik L Johnson
When confronted by KHV, you can expect high mortalities. In other words, a realistic expectation would be that more than fifty percent of your fish are going to end up perishing.
Should that scare you? No. It should „aware“ you.
Now, as a result of the increasing incidence of this virus among
Japanese import fish, dealers
(I can think of two, KoiConnection.com and Bob Bongiorno (SuburbanPonds.com)
are pre-emptively establishing a monthly testing regimen for KHV in
their livestock offered for sale. I think more dealers will follow
suit. And since the virus can hide, it is important that dealers test
all fish, even the same fish, each and every month. If the virus rears
it’s ugly head, it’s caught quickly and that group of fish can be
I’ve (ELJ) been managing a few cases of KHV this winter. The most notable case used cooling to
slow the losses, and then whenever possible, used high heat to push the
fish up past the virus-optimal temperatures and save the fish. It’s
worked in the majority of cases: which lived long enough to go through
Feb 8, 2003 –
„My kohaku (Matsonosuke) you told me to bring in is in the sun room, and
was very sick as you know, before. He is doing great and eating every
day …. Also, I brought in a orange gin rin Ogon who got completely
better too!!!!!! No torn fins, sores etc.“
So, why do some fish get warmed and die, and others get warmed and live wonderfully?
The answer lies in the virus action, combined with the concurrent presence of infection by bacterial opportunists.
First, the virus is devastating to the structure and integrity of the internal organs.
Victims report that the insides of the fish are positively liquefied.
Also, damage to the gills can be severe and so,
when these fish are warmed, oxygen exchange becomes crucial to a fish which is unable to sufficiently respire.
Secondly, when one tries to „warm a fish past the virus“ consideration should be given to the fact
that very few of these fish are free of bacterial secondary-invaders. Simply, most of these fish also have Aeromonas or Pseudomonas infections. So, CONTROL of these bacterial secondaries will enhance the success of heating KHV.
If one started the heating regimen with a careful examination,
observing severe gill damage could portend a failure (death) during the
heating regimen on that particular fish. And, without heating, the
chances for that fish are dire anyway. But at least a prediction could
be made for a more realistic expectation.
How should one warm a fish?
- The crucial
element is taking it very slowly, employing increased aeration and
reduced feeding at least at first. Do NOT pull on Superman’s cape when
it comes to dissolved oxygen!
I will quote an article on fish-warming I wrote for PondRx.com
Warming a fish up:
Fish in winter ice water sometimes need to be warmed up for various
treatments or to rescue them from genuine cold water illnesses such as
To avoid shock, the fish should be put in a very large vat of their own, icy pond water in your garage. I repeat, you’re going to use the icy pond water from your pond, that the fish is used to.
This vat should be at least 75 gallons in size or the temperature will equalize too rapidly and
kill the fish. They cannot climb up more than 10 degrees F per 18 hours
without serious stress or death. Let the vat slowly warm to garage temperature using the ambient room air.
USE NO HEATER. Do nothing to accelerate the warming process. It’s meant to be slow!
As the fish warm up, they will become more active. Make sure the vat is covered.
Once they have been in the
mid sixties for 24 hours, you can raise the temperature with a
commercial aquarium heater or a paint-bucket warmer, by five degrees
per day til in the low seventies.
Past that, if heating KHV,
simply aerate the dickens out of the water and jack it up five degrees
per day until you’re keeping the fish in the low eighties.