So yeah. I don't really want to add much as I like not having to do too many water changes but I do have an additional filter for this tank I can add on to keep up. But I was wondering what my options are.
I'm not even sure I want to add any fish really, I do like that the betta has lots of space to enjoy. But do you guys think he'd like more fish in the tank? Is it even necessary?
I'm looking for opinions on what you would do. I really love not having to change water in the tank often just because I have a 55 that needs weekly changes of about 30%.
Basically, do I need to add more fish for the sake of keeping the betta entertained or do you think he's better off how he is now and just leave this tank be? When this betta does pass on I will do a split tank but for now I'm gonna spoil him as I've only just returned to betta care and I don't want to get in over my head. After all, he's only been here two weeks.

I think it's still a bit too open in the middle area but he seems to enjoy it for now. I'll probably get another small silk plant or two to help fill it out.
There's some kind of plant in the filter also :X Came with my "aquatic" package, harhar. So I stuck one of them in this filter and two in the 55g filter.