Posted on behalf of Andre

Good Day,

We built our koi pond approx 4 years ago in kwa zulu natal. Our fish have
been thriving and lost only 2 the passed 4 years. The problem started about
2 months ago, we had just bought some new koi at the umhlanga Koi Show and
placed them into our existing pond.We then started loosing fish, our fish
were approximately +- 60 cm in length and were in fantastic condition.They
had healthy appertites and were spawning every season. We have now lost 15
of our best fish and we decided to drain the water and placed new water in
the pond, the pond is approximately 30,000 litres. The fish that have died
are bloated , gills are healthy and there is no sign of disease. The
remainder of the fish are very lothargic and have lost their appertites. We
have tested the waters Ph & Amonia levels anad they are in line with
specifications.


Please could you advise as we do not have any specialists in this field at
Tugela River Mouth.

we would appreciate any positive feed back as we feel rather dispondent
after this ordeal.

Best regards
Andre Botha

Your advices will be appreciated

Hi,

It is very difficult to identify the problem without knowing the history.
Please answer the following:
1. Were the new Koi quarantined?
2. How long after the new Koi were introduced to the pond did the problems’ start?
3. Water was the water temperature of the pond at that time?
4. What is the water temperature now?
5. Did any of the new Koi die?
6. Do or did the Koi jumped out of the water or “flicked” (scratch themselves against the bottom and side of the pond)
7. Are there any photos of the dead Koi?

I'm send you my answers for Pieter DeVilliers questions, could you please
forward.

1. Were the new Koi in quarantine - NO
2. How long after the new koi were introduced did the problem start - It
started between 1 & 2 weeks afterwards.
3. What was the water temperature of the pond at the time. - we didnot take
the temperature it was still winter +_ August
4. What is the temperature now. - +-22
5. Did any of the new Koi die - NO
6. The fish have been jumping and flickering, none have scratched themselves
on the bottom of the pond.
7. We have another fish that died this morning number 17, I will take a
photo and send you one shortly, as my sister is down here from JHb and she
is going to take the fish back to JHB to have it tested by a lady in
Pretoria on Wednesday.

Thanks so much for your help, much appreciated.

Regards
Andre & Annie BOtha
Tugela Mouth

Dear Andre

In view of the fact that the new fish did not die, it will probably not be water parameters.

In view of the fact that they did scratch / flash is an indication that there are parasites present.

The question might arise, why did the parasites not affect the new fish?

The answer is probably, it did, but ... parasites are normally only the primary cause of death. The primary infection of parasites cause and goes over into a bacterial infection. The Bacterial infection finally kills the fish.

The new fish might be immune to the bacteria in your pond due to prior exposure to that type of bacteria. However, your current stock might not be immune to new bacteria introduced by the new fish.

The first step should be to take a scrape and view the slide under a microscope. You will probably find costia or fluke or both, although it might be other parasites.

If there are none, you know that it is a bacterial infection and you do not have to treat for parasites. Without a scrape, you will not be able to pinpoint the problem.

If you find parasites, treat according to the species. If not, your problem is bacterial.

If it is an internal bacterial infection, you might loose more fish because a general treatment in the water will not be very effective. In most internal bacterial infections, you require anti biotics, but you should stay away from injections as long as possible. (Only consider when all else fails)

At this stage and in view of the seriousness of your problem, I would proceed with at least four Potassium Permanganate treatments two days apart. Increase your salt levels to 5kg/1000 liters and try to feed them anti biotic food(if they are willing to eat). You can mix terramycin powder (anti biotic powder) and honey with your food.

The potasium will address parasites and external bacteria, and the teramycin combined with honey might cure internal bacterial infection.

Hi,

I would like to agree with Paul, but looking at the photo of the dead Koi there is two things that stand out;
1. A hostile attack by a bacterial infection took place.
2. No visible lost of scales took place on the Koi in the photo.

This could mean that the parasite attack, if any was minimal, the fact that the Koi jump and flick show that there was an irritation or some discomfort present.

My guess is that the new Koi came from treated water that was infected by “Flexcibacter columnaris” that usually occurs at temperature more than 15*C in conditions stressful to Koi (netting, transport & show) still carrying the bacterial string. External tissues are attacked first of all, with the gills and fin as prime targets. Eventually the bacteria invade the bloodstream and there is a terminal spread to the internal organs.
By this time another bacterium called Aeromonas and Pseudomonas is most definite present in the pond as well. These bacteria commonly inhabit freshwater habitats, and are also present naturally, both on fish, and as part of their flora.
If the pond was overstock, all the Koi would be infected.

If I view the eye of the fish in the photo, it seems too “sunken in” which is a symptom, together with the reddish appearance of the dead Koi it could also be KHV, but the time period seems a bit to long and Koi will die within 7-10 days (so I hope that I am wrong on this) It was reported that the gills looked “normal” and not rotten?

I don’t think there will be enough evidence of parasites left on the dead Koi, but the testing could still help with the bacterium in the dead body.

Now, this is the hard part!
You will need to start all over to solve this problem, by killing all Koi in the pond and then disinfect the pond properly to get rid of this bacterial problem.

I know this is very hard to do. I lost 37 in 2004 with the same problem.

Sorry!

Hi Pieter, the red veins only appeared later on, there were no visible signs when the fish died.

"The fish appeared to have no sores or any other visible injuries, but when we took the fish out of the fridge to take this photograph it seemed that
alot of red veins appeared over the scales and the belly side area."

I think there are still hope for the remaining fish if treated asap.

Hi Paul,

heel onwaarskynlik, ek het ook so gedink in 2004. Die arme ou gaan net geld mors, hy gaan al sy Koi verloor...............ek sal Porsche daarop verwed.

Die rooi op die vis kan nie van yskas koue wees nie!!!!!!!!! Bloed stol as die koud word!



Enige weddenskappe?

Nee magtig Pieter, one hier in die Kaap het nie Porsches of M3's nie.

Paul,

alle grappies op 'n stokkie!

Hierdie mense het regtig 'n probleem, die nuwe vis dra beslis 'n "bacterial virus" , dit is miskien moontlik om die ander vis te red as die "nuwe vis" uit die dam verwyder word.
Maar ek glo dis te laat!

Hi guys,

I know we all want to help. But diagnosing a koi problem without two specific aids is a nightmare. And we can get it so wrong.

If you cannot scrape the koi and take a clipping from the gills the diagnosis is limited to - it "may" be parasites.

Without a swab and a lab analysis the diagnosis is limited to it "could be a bacterial infection".

The symptoms of KHV seem to have changed. When KHV first devastated collections in the late 90's everything died within 10 days the entire or at least 90% of the collection died. Now the symptoms seem to have developed into a few deaths over a longer period of time but still with 90% or so mortalities. Again without the swabs and labs tests the best we can do is "think" it is KHV.

When we diagnose pond side problems we go by experience and what we learn from scientific books. However, we are not always correct and our recommendations can cause more problems than the original disease.

A recent personal experience is case in point: After quarantining 6 new baby koi and introducing them to my pond symptoms of a parasite infection were apparent within about 7 - 8 days later. The baby koi had been bought from a dealers pond and at least two other prominent koi keepers had bought fish from these tanks and not experienced any problems what-so-ever.

My fish collection became extremely agitated with darting and flashing in the pond. Your diagnosis? Probably the same as mine - parasites. "Medication" was bought to bomb the pond and the various parasites but I do have a microscope so a scraping was done first. Not a single parasite. Another fish was caught - a fish that was displaying signs of stress after the agitation of the previous few days. Not a single parasite.

The fish became stressed and the "usual" symptoms appeared with fins clamped, some blood vessels prominent on the white of some koi and the fish became lethargic. One particularly bad koi was caught and sent for a swap and gill clip. The lab results were interesting - a bacterial infection. A list came back with which anti-biotics the bacteria were sensitive to.

A short treatment was done and I am very relieved to say I did not lose a single fish out of my collection. When the treatment was finished I did a 40% water change and I used bentonite clay - in a heavy dose - three times three days apart to bind and get the rubbish out of the water.

Now comes the really interesting twist. This occurred in May this year. In June and July I truly thought I was going to lose a collection built up over 20 years. As I mentioned not one loss. At the beginning September I sold 8 koi to a koi keeper to reduce the number of koi in my collection. The collection had recovered and the koi keeper was fully aware of the history.

This koi keeper phoned me to say he has not experienced a single problem with the introduction of the 8 koi from my collection - without quarantine. He does not have quarantine facilities.

Explain that one!

Back to our willingness to help - it is very difficult to diagnose accurately - especially over the internet. There are so many variables and in many cases we do not always get the full facts.

Be careful because as I explained above it is so easy to get parasite and bacterial infections mixed up without the aid of microscopes and labs. There is a difference between a bacterial infection and a viral infection. A bacterial infection can be cured a viral infection cannot be cured.

The sunken eyes on the koi in the pictures above – stress. Seen that many times before.

There is one further pertinent point – once koi become ill they take longer to recover than we realise. This is very temperature dependant. If there is not an immediate cure adding more and more medications may just aggravate the situation.

The koi’s own immune system is its front line of defence.

Kind regards,
Chris

Hi Chris,

Quote :

If you cannot scrape the koi and take a clipping from the gills the diagnosis is limited to - it "may" be parasites.

Without a swab and a lab analysis the diagnosis is limited to it "could be a bacterial infection".

Please let me point out that this should be done while the Koi is still alive as parasites will leave the host when it dies.
This Koi was refrigerated after death, and I believe that the “bacterium” or “virus” would be destroyed or very hard to diagnose.

Quote :

The sunken eyes on the koi in the pictures above – stress. Seen that many times before.

I believe that this was also because of the refrigeration.

Would you agree that by introducing the new Koi to the pond trigger this problem?

If this is KHV, shouldn’t the gills look like on the photo below?

Hi,

I agree it is a waste of time to try to find parasites on dead koi. Placing the koi in the deep freeze or fridge will cause the eyes to be sunken - so will stress on live koi.

The gills displayed could be KHV – you would need a swab and a test to confirm this. It could also be bacterial damage.

Mixing koi from any source has always been problematic in the fish industry. There is always a chance of a cross infection. This applies whether you have quarantined or not. Quarantine is the way to go but it is not a 100% guarantee that your collection will not be infected after introduction of the new koi.

Chris

Chris,

the pic is from a confirm case of KHV (George Mavrikis‎)

exactly -

until it was confirmed by a lab it could have been one or the other. This is the difficulty in doing a pond side or an internet diagnosis. There are several possibilities until confirmation is received.

Koi keepers must not be over hasty in adding medicine (poisons in controlled dosages) before confirmation is received.

We can suspect parasites but need a microscope to confirm this. We may suspect KHV but we need a lab to confirm this etc

So if we think it is something and we advise accordingly it may well be something else and the koi keeper can end up giving the totally wrong medicine.

Chris

Hi All

I have to agree with Chris on this one .........assumption is the mother of all @#$%^& up's in Life so never assume any thing rather make sure of your facts.

A lot of hobbyists have the assumption problem just because the don’t wont to spend the money on a microscope and lab work. They will rather risk their whole collection it is cheaper according to them.

Jip, a microscope should be one of the first things any hobiest must buy, and they can be bought for as little as R 350.00, although a better one is recommended.