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