On Mar 29, 2:36*am, (L u) wrote:
They are much more hardy than Goldfish..and they are labyrinth so they
can breathe oxygen. The water is crystal clear at last. The only problem
is the ammonia level is off the wall. I have to do water changes almost
every night, and even after I change like 90% of the water, the card
still reads a dark green!

WHY? Will the ammonia level ever drop down?

Maybe.maybe not. Your still dealing with a small tank and an overly
inefective undergravel filter I assume. Undergravel filters are a trap
for junk which produces ammonia. And all fish breath oxygen, they just
get it in different ways.............To be honest, IMHO a gold fish is
very hardy.......and IMHO your skating onthe edge by having labryinth
fish as if it or any other had to assimilate its o2 intake OUT of the
water they wold have died. This is not a sign that gouramis are more
hardy by any means, and its not how fish are really judged to be hardy
or not. The ammonia levels can certainly catch up and burn the fishs
gills and yes they do have gills, as well as possibly cause more
problems with pathogens that are deadly to any fish be it a labrinth
type or not.