I kind of like the bare-bones approach you took! If it were mine, I might add a simple background to conceal some of the hardware in back of the tank, but other than that, it's sort of elegant in its simplicity.
You should try a red cherry shrimp tank. They're really fun, especially in a low maintence tank with some low-light plants. Grab 25 and you'll have hundreds in half a year, they breed really well and are fun to observe. I no longer have mine, but when kept in a bright light they did get a DEEP dark red color. Good feeders for other things, too.
Is that a heated aquarium, because bettas are tropical fish around 78 F is optimal temp. They cant eat frozen fish either they need bloodworms, brine shrimp, and betta pellets they have tiny mouths. The betta looks pale so that's why i'm asking.