Take him back if he is not messed up any.. Oscars are peacful and they dont' do good with others who pic on them to death..
Dont' let a LFS person tell U that it can go with this fish or that.. READ up on them or ASK some one first before U buy.. That is like placeing in a adult Red Devil with the Oscar and hoping they get along.. they wont'.. The RD wil win the tank..
Get the meds ASAP and do as the directions say.. REMOVE your carbon from the filter if U can.. some are sealed..
So U are in brooklin?? I always wanted to see NY.. Hows the weather?? here it is nice and in the low 80 in the day.. Those dang hurricans are a pain, we missed most of Ike heavy rains thank goodness.. I am glad it is cooling off..
Have a great one, Barb