All my Koi are dying

[Flipp]

Last week my koi stopped feeding and most died over the next few days.

This has been very stressful as you can imagine, especially as they were all around 14 years old. They weighed between 8 and 10lb and prior to this were in fine health.
I have 2 koi left, one has started eating again but the other is still not interested.
The goldfish in the pond have been unaffected.

I've drained the pond and cleaned it. After refilling I added water purifier to neutralize the tap water, a bio filter booster to the filtration tanks and salt.

Has Anyone any ideas what may have caused this please?

[Flipp]

Hi sorry about the lack of background info in the above message, bit of an 'in despair' post.

I'll add a chronology of the events as soon as I can and hope someone can maybe advise me how to prevent this occurring again.

Since treating the pond at 2:00pm the goldfish are in 'turbo' mode, feeding OK and look a lot happier.
Of the two remaining koi one remains subdued and the other is a lot more active.
Fingers crossed that I don't have to remove any more tomorrow.

[COMET71]

hi,

we had a very similar problem and have so far lost 7 fish. When they first showed signs of lethargy and not eating we tested the ammonia which was high, so we did a large water change as per all the normal advice. however, they kept getting sicker and more fish stopped eating, then we lost three fish. we have now had some one from the local branch of the british koi keepers society (look them up on the web) they have a koi health expert (www.healthykoi.co.uk) who came and did a home visit. They tested the water and scraped some of the fish. They talked us through every thing that they were doing, even the scrapes, letting us all look through the scope! One of our fish was really sick with septicemia and they gave her an antibiotic injection. We still lost a few more fish that were too sick to save, but we gave it a good go. They came back today to check on the pond and did further treatments. I would recommend that you get someone in to help if your not sure of your next step. They will discuss your pond over the phone and will outline their charges.......worth every penny to save your wet pets.

[Flipp]

Comets7
thanks for your post, hope the rest of your fish make it OK.
I'll take a look at the link you posted. Fact is most of the damage has been done now, heartbreaking, these were real old fish and were my pride and joy.
I went to my local center this morning and the guy gave me some sound advice which I've followed, things do appear to be getting better now.
I'll post how things pan out it may help others to avoid the same problem.

[Flipp]

OK here's what's happened.

I need to go back a couple of months to encompass all the events in the life of my pond. But first a description.

Starting from the top.
A standard wet filter tank with sponge, brush and small tubing medium.
From there the water enters the top pond 6 x 3 x 18", filled with gravel/coral and margin plants for additional filtration.

After leaving the top pond the water falls 3 feet to the main pond via a waterfall. There is a further shallow area here where some of the water from the waterfall is directed via margin plants and gravel.

It then enters the main pond (14 x 7 x 4 to 6 foot deep) and is then pumped back to the wet filter via two pressure filters with UV's from the other end of the pond .
Two months ago everything was fine, in fact for 14 years all has been fine.


So what happened is this.
My fish had become more active after the winter and were feeding and looking well.
Six weeks ago, I introduced a single little fish into the pond that my wife had taken a liking to).
It lay low for a week or so then joined the others during feeding time. No sign of distress at this time.

Four weeks ago, I decided to upgrade my filtration system. The water had always been fairly clear with a little sediment in it, I wanted to achieve gin clear water so I purchased a couple of in line pressure filters with UV's.

A couple of weeks later and we're up to last week.
I began noticing a change in the fishes behavior.
The fish suddenly went off their food, were lethargic and began hanging around the shallow margins all lined up in a row by the waterfall.

Next day I found my two largest gold ghost kio floating on the surface, then next day my other two silver ghost of about the same size went the same way.

I replaced 2 thirds of the water and chucked in some water purifier to neutralize the tap water.

I was using dip tabs to check the water and noticed that the nitrogen and ammonia levels had risen, which I put down to the deceased fish.

Over the next two days 2 Tench, 1 Kohaku and 1 Yamabuki Ogon, all mature large fish died.

I emptied the pond completely and refilled it.

The remaining fish still looked unwell and on Saturday morning I bought a shed load of treatments etc.

By Saturday evening the remaining fish were looking a lot better, but all I'm left with is one Kohaku still not looking too well and one Moyo, the last of my prized fish.
The remaining fish, Shabumkins and goldfish are all looking OK and haven't really been affected by the disaster apart from being a little off colour.


I still don't know what started the sequence of events. I built and set my pond up 14 years ago trying to mimic a natural setting. I think I succeeded, but am now having doubts, where did it all go wrong?

Edit:
I bought a 'proper' testing kit today, readings are:

Before treatment:

PH 7.5
Ammonia .5
Nitrites .5
Salt .25

After treatment:
PH 7.5
Ammonia .25
Nitrite .0
Salt .5

[koimaster]

have you any air going into the pond chap ,levels are high i cant beleive what difference the treat has made on your readings!
there could be a whole host of things
from the changing/adding of the filters slowing the flow down back to the pond causing the balance to sway.
coupled with the up and down weather cause the bad nasty bug to be happy and multiply.

[COMET71]

Hi flipp,

We know just how you feel about your fish. We lost our sanke (septicemia) today, she had been really sick we also lost our hi utsuri. All our fish have names and although our's aren't as old as yours it's still hard to lose them. Just watching and waiting, but i don't look to good for the rest despite all we are doing Hope your having better luck with your remaining fish.

[Rising sun koi]

When you say you added a new fish, did you quarantine it before adding it to the pond? Are you 100% sure it was properly quarantined at the place you got it from? For all of your koi to suddenly go like that, may be some sort of infection/disease passed on from this one fish.

John

[Flipp]

Sorry to read about your fish comet71.

koimaster
readings were the same this morning 0 nitrite but ammonia level still .25.
I've never used an aerator in my pond and have relied on the waterfall.

Rising Sun Koi, no I didn't quarantine the new fish, which is still happily swimming about and doesn't appear affected at the moment, so you may be correct, the new fish may have been carrying something nasty.
But the weather has also been pretty awful lately which could have unbalanced the equilibrium.

OK this morning no further loss of fish but they were once again gathering under the waterfall and a couple of the goldfish don't look to well now.

I decided to put plan 'B' in action.
Panic!

I've put all the fish in a holding tank (my sons 10'x2' 6" deep swimming pool:-) I have also put in an aerator and bought 15m of tubing this morning and redirected all the filters from the pond to the pool.

The reason for moving the fish is because I'm concerned that if any more fish die they may sink to the bottom and cause more problems. At least this way I can check every day and remove any dead fish before they cause a problem.

I emptied the pond again today and will power clean it tomorrow, I'm also going to dig out and replace the media in the top pond and basically start from scratch again.
Once the balance has returned to normal I'll reintroduce the fish.

I'll certainly be more careful introducing new fish in future and respond a dam sight quicker to the first sign of imbalance in the water or distressed fish.
I think because everything had been going so well for all this time I grew complacent.

Thanks again everyone, I'll update again as things develop.

[koimaster]

i would say if you are having the up and down weather im having stormy too at time i would not rely on a water fall to suply the o2 i would add more myself via the means you have brought.

i do hope you sort your problem out and dont lose any more fish
wishing you all the best mark