I'm having a trouble with sudden Goldfish and Koi death in my aquarium
that I believe is related to water quality.  I was hoping someone could
point me in the right direction.

I have a 70 Gallon aquarium, Fluval 404 Canister filter using Black
Diamond Charcol and White Diamond ammonia remover.  There is an air
stone, the filter is changed around monthly, and partial water changes
at about the same rate.

There are about 12 fish in the aqaurium with the execption of the last
Koi that passed away this morning, all fish are under 6 inches in
length.

Last night the fish were fine, this morning everything looked okay as
well.  I get home from work 10 hours later, the large koi (the last koi
in the aquarium) is dead, and all the others are covered in a milky film
and red veins are visible around the fins.

This is about the 5th time this has happened this winter (the fish spend
the summer outside).  With the exception of the last 2 times, it has
never affected any of the Koi before, only the Goldfish.  Now all the
Koi are dead.

I assumed this was a classic symptom of ammonia poisonning.
Unfortunately at times White and Black Diamond are hard to find locally
and I have to resort to the cheap stuff.  Assuming that this was my
problem, I have since started buying filter material off the internet.
Hence only high quality filter material in the aquarium lately.

I also purchased a little disc that sticks to the glass of the aquarium
that is supposed to turn colors when ammonia builds up.  It never
changed colors, I used two different ammonia test kits on the water
tonight, both report 0 PPM.

What else, other than ammonia can have such quick effects?  And what can
I treat it with?

The fish respond immeditely to a 50% water change, and within a few
hours lose the white slime, and within a day or so the red veins.

The problem seems to be become more frequent, and happens at a quick
pace.  Originally I would catch it before any fish died, now within a
few hours of abscene the fish are dead.

Anyone with more experience than me?

Chris Ross
chrisr{at}axess.com
1:167/565



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