I had a young oscar die and replaced him with an older Oscar. everyone is getting along great but the new oscar has eaten maybe 6 med pelets in three days. he does not seem to like the blood worms, at least enough to stop my young Oscar from eating them first.
So the question is, are they like dogs and will eat when they get hungry? or do I need to find out what he likes?

Thanks

One of oscars nicknames are river dogs.

Your new O may be sulking as he has been moved to another tank (most likely) or maybe he has got used to another sort of food and only wants to eat that. Just carry on as you are and see how things are in a week. If he isnt eating like a pig then dont feed for a couple of days and try again. If that dont work dont feed for 4 days and give it another go.

Can you post your water test results so we can eliminate that, test for ammonia, nitrite and nitrate

That's what I was hoping to hear, have you brought older fish in before?
My water is pristine as we like to call it 0,0,10 78f but my PH is hi at 8 but I'm not going to mess with that.
the problem is that my young O will eat antthing and everything with in 20 sec and does not give the the new guy a chance to taste the good stuff.. I'll give it more time. I just wanted to know if they would adapt and overcome as we do in the Corps...

Corps? I believe you are refering to the the Marine corps, If so Semper fi...Where are you currently stationed, it's nice to see another Devil Dog on the site. I would not worry about the current feeding problem, it will balance itself out and Oscar when older can go weeks with out food with little ill effects.