if ick just add salt and raise the temperature by 2c degree
if you really need to use med, normally i cut the dosages by half of what the instruction says
with half dose i add half(of the half) and wait for a hour then add another half
Why would you reccomend raising the temp by 2 degrees C, if you dont know what his current tank temp is?
Ick, and pathogens like it, dont like salt, but it wont kill it(especially if you reccommend "just add salt")... you'd need very high salinity levels to kill it and get it during the right time in its life cycle...
Aros do fine at full dose meds... These are not scaless fish or fragile fish..... just expensive/prized, so we tend to treat them as such
Sorry to pick you post apart, but recommending incorrect treatment for an unknown problem(we still dont even know for sure what the problem is) is something that is done far too frequently and peoples fish generally suffer because of it....
Without pics, i wouldnt be able to say what this problem could be for sure... but i feel comfortable enough with the description to say it is not ick.... OR gill flukes...
Sounds to me like it could be one a few things... My number one suspect is ammonia/water quality... check your parameters...
Second could be from an injury.... other fish/ tank deco, or even rubbing the eye along the side of the tank....
Either way, id start with heavy water changes until you can provide water parameter readings, and pics...
good luck.