In article k.net,
says...
Sorry that I wasn't clear. I am reading 0 on ammonia, 0 on nitrates and
acceptable on PH.


What you described was a sick fish that got better when
you gave it provably good water. What more proof do you
need that you have a water quality issue?

And seeing a reading of zero for nitrAtes is not normal unless
you just finished a 100% water change. You probably had a
bio-filter crash. (Or maybe you have old test kits that
are giving false results?)

I thought 20% changes once a week were more than enough on a well
established and cycled tank?

For a well established and cycled tank, you change whatever it
takes to keep nitrates to an acceptable level. How much and
how often depends on a lot of factors -- stocking levels,
live plants or not, etc. The point is not sticking to a rote
formula: it's to keep the water clean so the fish stay healthy.

I strongly suspect that if you start doing 25-50% PWCs daily
for a couple of weeks, your fish will improve.
Ok, _now_ will you go read http://faq.thekrib.com/begin-cycling.html?