I have a 2.5 gallon for a betta too, I just started mine on live plants, before I was just using plastic. My doesn't look nearly as amazing though, hopefully it will look good like yours one day too. I love Shurbert coloration, such a nice orange!
Hey, you said that you don't have CO2 in the tank right now. Did you know that you can make an AWESOME CO2 reactor with the filter you have right now? It diffuses better than a lot of glass diffusers, and it's very small. Here's how you can make it: