Thanks for all your help.
I obviously messed up on this one and feel responsible for the fish
deaths. It was the hot weather that encoraged me to mess about in the
pond and, I thought, sort it out while cooling down. Yes, it is a
shallow pond. I've moved the survivors to a smaller pond, where they
are a bot crowded, so I need to get them back as soon as possible.
Obviously you don't know the extent of the damage, but can anyone give
a ball park figure of how many days I should wait? Or should I go the
whole hog now and clean the whole pond out? I had thought that the
gunge at the bottom was helping to root the plants. Wrong again I
suppose?