It *almost* looks like a bacterial bloom, but it has a green tinge to it. I have maybe 4 live plants in there, the rest are fake because I know he will try and tear them up.
The substrate is sand. I have two Aquarium Co-op sponge filters, one a large size and one a medium. Two fluval heaters. And I use a fluval 3.0 above light, although I have been keeping it off hoping that some of this will die down.
Here is a picture of my Oscar, Tyrion, he might be about 3 inches in length.