I bought a new air pump and i think it is way too strong because I have a 7" air stone and it looks like it's exploding and there is a lot of noise and it just does not look good so today I am going to buy a splitter so that it will bring oxygen to both of my tanks and I am hoping they make a 'splitter' will an adjustable air flow so I can get it just right. Now heres my q? How much oxygen do oscars need in their water and is it possible to over oxygenate their enviroment?

As long as your Oscar is not breathing heavily, i.e. opening and closing his mouth constantly, you've got enough oxygen going into the water. If you do see your fish starting to open and close their mouths, or they hang under the surface of the water then this could be a sign that there could be oxygen depletion in the water. This can especially happen if the water is too warm, sometimes during summer months.

I better just mention that fish breathe heavily for many other reasons as well, not just because they haven't got enough oxygen.

Yes. Adding an extra filter would probably be better, since it not only cleans up the tank but it also adds just as much oxygen as your average air pump.

I am going to take a video because they all open and close their mouths but i always thought it was just what fish do like other fish. Amonia-Nitrite 0 Nitrate anywhere between 10-17 and the heat is set at 80.

All an air pump does is ripple the surface. A rippled surface has a larger surface area than a still one. It is surface area that determines the rate at which oxygen can go into the water.

As artemis says an extra filter that has the output positioned to ripple the surface will do that same job. Have an air pump if you like the effect