I was just looking through the forum on another Oscar Fish site and I noticed that you posted the same question. I shouldn't say this, but blimey, the guy who replied doesn't half like the sound of his own voice [he stays with tongue in cheek, no offense meant]
Okay, what he's saying is partially true, feeder fish can on rare occasions contain diseases or illness which if consumed by your Oscar, could be passed on. Hand, there are other things that contain better nutrients so I would personally o feed them a couple of times a week.
I have a small community tank and if my memory serves me well, only on one occasion have I brought home a small community fish you may buy to feed to Oscar that has has then become ill and died, the rest of them have been perfectly okay, I think that says something. Check your local fish store out, are the tanks really clean, are there any sick or dying fish? if everything checks out okay, I don't see any problem in buying feeder fish from them. a lot of these guys get a little bit excited when they read of people feeding about Oscar's feeder fish, if you proceed with caution, then your Oscar shouldn't come to any harm. If you want to be really cautious, quarantine the fish for around a week or two, if it has gotten a disease, it should show itself in that time. But don't let these guys frighten you into not giving your fish live fish on occasions.
My tiger albino oscar, named Og, Has a red spot above his gill. The water all tests normal and i have kept up with tank maitnience. He is a bout two years old but i have only had him for a few months. I keep him in a 55 gallon aquarium by himself with a good charcoal filter and nice heater. I usually feed him cichlid pellets and feeder fish. He also does not seem as active since this spot above the gill has come in... Please Help. Also i am new so Hi and very nice site... 
