Wow what a beauty, your guy is gorgeous!!!! I think I want him lol.
Okay well a single male betta requires a minimum sized tank of 2.5 gallons to remain healthy and happy. A tank of this size would require two cleanings a week.
Also bettas are tropical and cannot handle fluctuations in water temperature because it causes them extreme stress and compromises their immune system which puts them at risk of all kinds of nasty illnesses and diseases so a submersible aquarium heater with a thermostat is a critical piece of equipment to keep your betta healthy.
You will also need to add water conditioner to the water that you put in his tank because tap water contains chlorine and a number of heavy metals that are toxic to fish. Adding a water conditioner to his water every time you clean his tank will neutralise these substances and make the water safe for him. The water conditioner must be added to the water BEFORE the water is added to his tank.
Also be careful what decorations you put in his tank, bettas fins are fragile and tear wasily so use silk or live plants instead of plastic and avoid anything with sharp point or edges. Also ensure that the filter that you buy has an adjustable air flow because bettas do not like a strong current.
these are just some of the basics of fish keeping, if you need to know anything else don't hesitate to ask