i am very serious about this hoby and i wouldnt waste $25k if I wasnt. i had the fishes in the 90G and 55G watching them for 3 months before i had the problem with ammonia which may have been the cause for the ich to begin with. i did use prime and after that didnnot work AMQUEL which did not work either so i defcided in an crazy act to moven them all to the DT (had been cycling for 2 month and had no ammonia (still doesnt have it)
once i decided to move them to DT i had no choice but move them all to avoid aggression which did work since they all get along.
moving all the fishes back into the 90 will cause a major stress. the ones that had signed of ich were one yellow, the 3 blue, the purple and the achilles. the purple is cleaned. one blue is almost cleaned the yellow is better too. now we have 2 blues and the achilles which is the worst. i noticed the purple had spent a lot time with the cleaning shrimp and so did the blue. i also saw the yellow there too. i noticed the shrimp on the achillis today. maybe is the shrimp and not the medication. but i have used the ich attach before and it worked since i have no shrimp on that tank. one thing i can guarantee is i am a caring reefer and also serious about it. i am not going to use copper on the DT for obvious reasons. any other medication that will not kill the bacterias i will be glad to use it. thank you
If your setup is correct in terms of having enough cycled medium, circulation and flow and no addition of new livestock, and if there has not been any ammonia problem for two months, then ammonia problem should not happen. Did you use any drug that harms nitrification bacteria?
Nitrification is very dependable; it is an aerobic process and as long as you have good circulation, gaseous exchange, no salinity or PH shock, nitrification is certain.
I suggest that you do not use the term "stress" loosely. More precisely, is there no ammonia, good gaseous exchange, circulation, security, space, and nutrition for the fish?
"Stress" really has little to do with ich. Ich is a matter of confinement and lack of dilution of the open sea, of a pathogenically closed tank. Eradication is necessary.
Cycling the medium for QT in advance works well to eliminate ammonia in QT no matter how many fish and how big they are; even 10 10-inch fish. (unless one has to use a drug that harms nitrification bacteria, usually an antibiotic to treat bacteria infection).
In your situation, cycling enough medium to support all fish will work to eliminate ich by treating fish and then waiting for DT for fallow out, total about 12 weeks. Cycling this way often takes about 3-4 weeks; then all your fish will be supported without ammonia.