c_paan: It could be possible to grow plants with oscars. It is best to have small oscars (less than 3"), and to use strong plants like Amazon swords, Jungle Val (americana), and Anubias species. They will need time to grow in, but once they do, they should survive your oscars.
Flourite Onxy is not necessary to grow plants. I used it in this tank to try something different, and to show you guys what it is like (since there were and are many questions about it). It's very similar to regular Flourite, only all black, and fine grained.
Styxx1: Good to hear your tank cleared up and is doing well! From my observations on a variety of tanks and their parameters involving light, CO2, and nutrients, I must recommend CO2 more than light.
Here's what you can expect by adding CO2: much larger plant growth--I mean that your plants will get very, very large regardless of the light you have. Light only makes them grow faster. Some stem plants require higher lighting, but with the plants you have, your light is fine. Don't forget to use a good quality fertilizer such as Seachem's Flourish or Tropica's Master Grow. The Mondo Grass you have should be taken out and taken back to where you bought it; it is an emmersed plant (for terrariums), not submersed (aquariums).
I have 45 regular flourescent watts of lighting on mine. The bulbs are 1 GE Plant & Aquarium, 1 GE Chroma 50, and 1 GE daylight. I need to buy a new CF bulb for my fixture. For your fish, look for small fish (small fish for a small aquarium).