Sorry for the delay in responding, I was unable to get to a computer
for the past week.

It was probably too late for these fish. I had already isolated the
fish from the tank, fresh water (declorinated) and a new airstone. They
didn't make it. When I cleaned it there was some gunk, mostly uneaten
food, but not a lot.

BTW: the Corey and the snail seem to be having a great time in the
tank. Is this another indication of a problem?

I normaly do a breakdown of the filter and a 50% water change weekly.
The carbon filter gets changed every 60-90 days (I will move it to
every 4 weeks). The sponges have not been changed in 10 years. They
get rinsed clean each change. I have had the same fish survive in the
tank for 8+ years without any problem.

I will take your suggestion about the full cleaning and change of media
and I will let you know if I have better luck with the next batch of
fish. I hate losing fish.

Thanks for your help. Hopefully there won't be another tragedy and we
can swap stories and techniques about beter times.

Ginger