New here - all my koi are dying!

[squeakywee]

Hi all,

I have a large pond with a lot of fish - too many to count. These are mostly goldfish, but I had 5 huge koi - one gold, one japanese and 3 silver ghost - all around 19-20 inches long. I've had these fish for over 15 years. In the past two days all 5 have died Does anybody know what could've caused this? So far all the goldfish seem to be fine. Nothing has changed with the pond recently and I haven't added any new fish for years so it can't be that a disease was introduced. It's all so sudden All of the dead fish look fine to my eye, with the exception of the gold koi which had a sore on his head for a week or so. I have a photo of two of the dead fish if that would help diagnose them.

If anyone could offer any kind of idea what caused this I'd be so grateful.

Thanks,

Kat

 

[dieselplower]

Can you tell us any more about this pond? Things Like size, filtration, pump gph, aeration, plants etc? What has the weather been like recently? I don't think anyone could give you an even good guess without more information. Also do you have ammonia, nitrite, nitrate, ph, or any other readings?

 

[Mmathis]

Welcome, but sorry to hear about your fish! It's especially hard to lose them when you've had them so long!

I ditto what diesel asked. It would help us to help you better if you could provide some information about your pond. I'm still a newbie, but one thing I've learned is that ponds are a fine balance of life and chemistry. If one thing gets out of whack, it can have an effect on everything. Most of the time, problems like this are due to an issue of water quality due to overcrowding. So that's why we ask about pond size, fish load, water test results (ammonia, nitrites, nitrates, pH, KH, etc.), and what you are using for filtration & aeration of the water. I understand that the UK has been having unusually warm weather lately. That can be a problem. So there are many factors to consider.

You say you haven't made any changes lately -- that's good to know. So no new fish, anything like that. But, goldfish and koi do have lots of babies, so even without adding fish, you're fish load could have increased.

Also, one koi had a sore on its head -- yes, pictures are helpful, if you could include those.

 

[dieselplower]

Also, did u notice any strange behavior recently? How about gulping at the surface?

 

[Dave 54]

Hi First off can you give me your water peramters Ammonia, Nitrite, Nitrate, Ph, Kh , next can you teell me when you last did any maintenance to your pond i;e water changes filter maintenance etc ?
Alott of people have noted that there have been exeedingly high temeratures going on around the world, infact here in the UK weve seen our pond topping 26c, as you well know coming from the South east ( may I ask where) .
You havent given us an idea of your pond size what filtration you have, size of U/V-C etc all are important as to getting to the bottom of your problems .
I'll also hazzard a guess your temperatures have been higher than ours ???
To combat this weve been pumping more air into our system and all our koi are fine, we like yourselves have koi that have been with us for many a year two of them for the last 27 years and we would die if we lost them because koi canand do live up to 80 years or more.
Maintenance has to be do on a regular basis as have water changes we drain 30-40 of the ponds water each week and clean the vortex out at the same time.
The next two filters are cleaned twice yearly once in spring and once just prior to winter and they are an important step taking you into and out of winter.
Do you have much in the way of detritus such as dead leaves etc in your pond , if so it'd be an idea to give the pond a clean and perhaps net against it .
We use a company called Norfine nets of Norfolk see link :-

http://www.norfinenets.co.uk/

The 6mm hexagonal with bungiestraps to hold it across the pond and around the pond believe me when I say it stops leaves , they are value for money ours is in its 6th year of use.
As you have said your koi look normal there was nothing wrong with them when they died .
I would personally add more airstones into the pond keep a sharp eye on your Ph and Kh check out this thread as well :-

https://www.gardenpondforum.com/topic/12352-high-temperatures/

Try to follow it best you can if you have anymore deaths we'll have to re-think and perhaps do a scrape for parasites who believe it or not are present in our ponds and just looking for a chink in our fishes armour.
Remember water changes, equipment maintenance and general testing of the water go a very long way into stopping fish deaths.
It may also be an idea to look at the ponds population, do you have too many goldfish in the pond if so sell some on .

rgrds

Dave