hi i have two oscars that i bought at the same time both at 2" but one has grown to 5"and the other seems to not have grown at all ,is this becaues the larger has eaten more food or can there be a growth problem with some oscars and if not what is the best thing to feed him to help him grow ?

Just feed them regularly, Oscars like people grow at different rates!

When i have 2 fish competing for food, i try to feed them in their own corner.
Works for me.

I bought both of mine at about 3" - one of mine grew so much faster than the other for the first month or so and then all of a sudden the smaller one had a growth spirt and they ended up being about the same size - about 1/2" difference between them. The larger one was eating more than the other and it turned out there was a dominance issue. That resolved itself though. I keep mine on a rotating diet to keep them interested... pellets, blood worms, beef heart and feeders (only once a month). They seem happy and share fairly well.