Yesterday and this morning.
My next door neighbour has been feeding over the road's gold fish, they in an outdoor pond, while they are on holiday. Humans not fish! 
He came over to me yesterday morning in something of a tiz as he had found fish floating on the surface of the pond, stone dead.
Helped him rescue all the live ones we could find and capture, 20 odd, from what I can only describe as a dead pond, and put them into containers filled with rain water, and a little water from the pond added, as that was the only thing I could think of doing at the time.
They most certainly would have vrekked if left in that putrid water, as it was a dark green with not a sign of any oxygen in it, and smelly.
Far far too many fish in it to start with, as we counted 20 floating on the surface.
We checked this morning and all in the containers where lively and headed to the bottom when they spied us, but two of the largest and three small ones where past it, the large ones looking so yesterday but we thought they may recover.
The dead ones went back into the pond.
Neighbour saw the head of what must have been the largest of the fish lying on the lawn, no doubt it having been the supper for the cat he spied the day before exiting the property.
He said he wont be volunteering to feed the fish in future.
Geoff – Does make one wonder.