You are almost certainly killing your fish with kindness! OVERFEEDING!

I too am in UK - "exceptionally mild" winter is a relative term relating to
comparison with weather in general. It is now (and will be) too cold to
contemplate introducing new fish into an outdoor pond.
Fish become very inactive Autumn to Spring - I stopped feeding late Sept,
and don't plan on feeding again till late March/early April (there's
sufficient natural food in my pond from plants and water life to support
them).

I've had my pond over 10 years, the only fish I've lost are from disease and
heron - the disease was in Summer last year, from new fish. One of the
first things I learnt was the danger of over-feeding - uneaten food
decomposes and pollutes the water, and this lesson, practised over 10 years,
seems to be true, since the one and only fish I have left (after the heron)
is a large Koi which was already large when I started the pond.

Hope this helps, Len.

"Smith" wrote in message
...
Our pond is approx 3775 litres and we have around 40 goldfish in there,
plus frogs, a few plants and a fitration system which has been running all
winter.

The winter this year has been exceptionally mild and most days we have
been giving the fish wheatgerm sticks.

Oveer the past fortnight, we've lost 7 fish. (2 biggish ones, but the rest
juvenile black/silver ones) The symptoms seem to be sluggishness,
difficulty keeping upright, followed by a pigeon-chested, bloated look and
finally death. I just euthanased the most recent one with clove oil.

Any idea what the problem could be? Could it be the feeding? I've not
given them anything except wheatgerm since about October last year.

We've just got new foam filters and a new UV for the pump, but at the
moment, I'm reluctant to disturb anything. Checked the pH and it was
neutral.

Don't know what this could be, and any help/suggestions would be
gratefully received.

Tracey