So I have a Betta fish (his name is Oscar) and he is not active at all!?

Betta fish will blow bubble nests at the surface of the water if they are happy. This doesn't mean your fish isn't happy if he doesn't blow bubbles, however.

One problem is, the bubbler you have in the tank probably makes the surface too choppy for him to blow bubbles of his own. He may be happy just hanging out, he just can't blow bubbles.

You can get these floating rings for your tank that are large enough to provide a calm surface perfect for betta's to blow bubbles.

Live plants. Floating plants, java moss as a "carpet" along the bottom, tall plants, short plants, big leafed plants, small leafed plants.

Floating plant: Duck Weed (tiny plant) or frogbit (larger plant). You can make a sort of barrier to keep the floaters in one area or away from the filter.

Java Moss: Easy to grow plant that thrives in fast moving water but will grow in almost any circumstances.

Tall Plants: Jungle val is my favorite, but it gets pretty large for a tank that size. You could always remove the tall plants. They do multiply fairly quickly so it should be alright. Otherwise Alternanthera plants get fairly large (as long as you don't get mini ones ;) )

Short Plants: This is a little harder. Might want to focus on the easily trimmed plants like Bacopa.

Big Leafed Plants: Anubias plants. Low light. Hardy. Grows steadily. Has large leaves.

Small leafed plants: Bacopa has small leaves. Dwarf Baby tears is small, but would need CO2 and that's not easy to get and is difficult to regulate.

Plants do help the fish explore more. Their environment would be constantly changing.

Keep in mind that bettas are naturally lazy fish and aren't really all that active.

Hi Oscar, how are you?