glad to hear everything is clearing up. dont jump to the conclusion that everything is 'fixed' though
reframer had a good suggestion, you might want to feed some peas.
When fish are shipped large amounts of ammonia accumulate in the shipping bag. This doesn't pose a threat to the fish because in the closed environment CO2 has also accumulated reducing the pH of the water and keeping the ammonia in its less toxic form. Once the shipping bag is opened to the atmosphere the CO2 escapes, pH rises and the ammonia becomes toxic killing the fish. This is why most wholesalers, retailers and shippers use the plop and drop method.
Since the CO 2 would escape from the bag (?) the pH would not be depressed, so the argument is negated (and the fish would be experiencing higher ammonia, lower ammonium)?