"Spider" wrote in message
...
My pond is a smallish cascade affair. About 10yrs ago I kept fish (Golden
Orfe) in it. However, the local heron scoffed the lot, so many years
passed without fish. Because of this (and perhaps foolishly) I planted a
laburnum tree a few feet away.

Pure guess......might be a build up of poisen from the tree. Not something
I'd normally suggest at this time of year, but a major water change may give
a temporary respite.Use temp matched dechlorinated water. Long term, I'd say
either the fish or the tree have to go
--
Pete C