Thread: Koi Deaths

Hi.

Looking for some advice please as I am stumped.

25,000 litre pond built up from the ground. Netted. Established for 12 years. 2 very large multibay filters. 4 water outlets into the pond giving a lot of splash and circulation all on the back of the pond. 8 airstones. There are definitely no oxygen issues. Liquid water tests show 0 Ammonia, 0 Nitrite, PH 7.4. Nitrates minimal. UV light run via a separate box filter.

I have Koi, Sturgeon, Orfe and Wakin goldfish in the pond. I empty and refill around 2,000 litres per week via the filter and top up with treated water.

4 weeks ago I rehomed 10 x 15 inch Orfe out of my pond. 3 days later I replaced them with 8 x 10-12 inch named koi at a cost of just under £1500. I bought them from an online retailer that I had used a few years back and had never had issues with any fish from them. I also had some goldfish from them which I added into the pond at the same time.

In the last 18 days all of these Koi have died. Each morning I would go out to the pond and 1 would be floating.

No physical symptoms of any disease or injury. There had been no flicking or jumping. They had been eating initially but I'd notice a fish hanging around a corner or part of the pond on it's own, not eating, then it would be dead the next day.

As I say nothing physically wrong with the Koi that can be seen.

All of the new goldfish purchased and alive healthy and well.

My original fish that are already in the pond (koi orfe sturgeon) are absolutely fine, no deaths, no illness, all healthy eating and acting as normal.

The pond isn't overstocked, no aeration issues, good food, no change of pollution from runoff etc.

Any ideas what has happened? Is it something I have done? Were the fish dodgy?

I am annoyed as you can image because they were lovely fish and they have cost a fair bit of cash.

I just cannot understand what has happened.

Originally Posted by Koiboy75

Hi.

Not yet, I wanted to check to see if it is an issue my end before contacting the seller as I want to make sure I haven't done anything wrong. I had thought KHV but all of my original Koi are fine.

Hi/ That's a lot of fish, The Guy who reportedly had KHV lost his £20.000 collection. And it was a true case, because Bryony from London was involved. I was listening to a discussion on youtube at the weekend and one dealer stated heat ramping isn't always guaranteed to show the symptom of KHV.