Simply Koi and More Koi

Hi all, hope you are well.
My fish came out of winter happy and very hungry.
Then about 3 weeks ago they seemed to slow down, the feeding wasn't quite as vigorous and I expected the dreaded bugs.
I've noticed a few of them lunk out the water quite regularly. 1 more than most, which I have scraped 3 times and all is clear.
One of them is swimming sometimes erratically which is a concern as it's a large fish.
I have scraped all of the fish and maybe 3 of the most affected twice, and all I've found is one fluke.
They are flicking a little, all fish are spotless apart from a few lost scales.
I suspected the nearby Laburnham tree the culprit so have done a couple of large water changes in the last week which has perked them up a little but the symptoms are still there.
Today I stripped the bead down and it was spotless.
The bead is cleaned around 4 times a week, at least 30% water is changed a week, pond is 5500g, and water tests are always under control.
Today I sedated 4 of them a little to get a better mucus scrape near the gills, pretty much under the gill plate but still no luck.
The gill filaments' looked good, very dark red, apart from one was slightly off colour.
I have found all the parasites in the past, if not on my fish on friends and family, and have been the first point of call for many in the past, but I'm really struggling here
Think I'm going to leave it for a couple of weeks and see how it goes. I'm not about to chuck some chemicals in for the sake of it.
They are still feeding, but not as they should.
Any advice would be welcome, £100 for the first person to come round and find bugs on my fish
Regards
Dave

Dave

I would try a gill biopsy sometime these critters are deep in the gill fillaments

dunc

Thankyou Duncan I'll give it a try.

Well I did the gill biopsy and couldn't find a thing.
I have done a further 5 scrapes also 2 from the gills and no parasites were found.
I still have 2 fish regularly lunking out the water, and sometimes I catch them sulking on the bottom.
I had a fish damage it's side a couple of weeks ago, about the size of a golf ball. It looked sore, but I didn't touch it and it's healed up well, so I'm thinking my problem isn't bacterial.
I'm thinking it's gill related, maybe a dip could help?
Many thanks
Dave

increase the oxygen see if that helps it may be low oxygen tension

Cheers Duncan, shall do

Hi did the extra o2 make any improvement

Hi Amanda
sorry for the late reply, just got back from my holiday.
Well I did as Duncan suggested and increased the oxygen, there has been a little improvement but
there is one fish that is still lunking quite a bit.
They are all eating well so I'm just going to suck it and see.
I don't think that the problems I've had are a result of poor aeration as I've always had the aerated bottom drain on, I also have 2 large sieves and a large shower on 5500g.
Not sure what's been going on this year!! Been a weird one!!
Dave

koicarpus wrote:Hi Amanda
sorry for the late reply, just got back from my holiday.
Well I did as Duncan suggested and increased the oxygen, there has been a little improvement but
there is one fish that is still lunking quite a bit.
They are all eating well so I'm just going to suck it and see.
I don't think that the problems I've had are a result of poor aeration as I've always had the aerated bottom drain on, I also have 2 large sieves and a large shower on 5500g.
Not sure what's been going on this year!! Been a weird one!!
Dave

At this time of year the water tems are higher meaning the water hold less oxygen that’s why I always have my water bobbling the same with my filters 120 litres going into my filters with 60 litres into my pond the pond is 1500 gallon’s