Betta Fish: Advice Needed – Tank Size

Hello everyone! Just wanted to turn to the community for some advice about tank size. My boy Harley zooms around quite a bit compared to my other betta (Mellow) and it’s making me wonder if I need to upgrade him to a larger tank, maybe 10 gallons? I don’t want to confine him to something smaller seeing as he’s so active, if the extra space would be beneficial for him. He’s currently in a 5.5 gallon. Any advice would be greatly appreciated!