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