Andy I would test the water myself with a testing kit that used test
tubes and not strips. ( I had a pond doc at my house this spring- he
was an idiot). Could you be more specific on how many fish were
stocked in the pond, the pond size and filtration, pump size, ect. It
is usually poor water quality that kills fish, so that would be where I
would investigate fully. Also overstocking leads to decreased oxygen
levels as someone else mentioned, with most fish dying in early
morning. If any more fish die (and I hope they do not) I would get
them autopsied by a fish vet or at least scoped for parasites, disease,
ect. Sorry about your fish loss.


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Koitoy