I know nothing of Koi or Goldfish for that matter but anyway. Could the
Goldfish fatalities be age related? I'm sure Goldfish must have a lifespan
longer than 4 years. You say that they've been together for four years. Fish
most definitely get attached to their tank (pond) mates. Maybe 1 of them
died and the others followed suite due to stress of a lost loved one
REALLY, It might sound absurd but a guy over on the freshwater group
recently had a pl*co that died, one of the Oscars that shared the tank with
pl*co stopped eating for a month. So you see, fishies have feelings

By the sounds of your setup I reckon your water quality is fine but as
others suggested maybe you should just go and buy those test kits anyhow
just so you have them and just to be sure! If your water testing turns out
fine then I suggest adding more Goldfish to the pond to alleviate the wounds
from the loss of a loved which the other fish may or may not be
experiencing.


"Wally" wrote in message
...
I have an established pond - 2500 gallons, great filtration, 4 years old
- with about a dozen koi and a dozen or more goldfish. Koi are about 12
to 18" long, goldfish are about 2 to 3" long. Water lillies cover about
2/3 of the pond. Waterfall is a sheet of water about a foot across that
drops 2 feet, with smaller waterfall about 6" across makine 2 small
drops. Water is crystal clear.

Up until this past week I have had zero fatalities. But as of today I
have had 4 dead goldfish. They appear to have no parasites, though one
had it's fins chewed up (but that could have happened after he died).
But the koi all seem as happy as ever.

What should I do to start narrowing down the problem? Is it an oxygen
problem, or an imbalance problem, or??? Too many water lillies? I never
test the water - what should I test for?

Gary