Try to find Hikira Betta Biogold pelets...Cheap (Petmart+Walmart) Feed 2 in morning and 3 at night...
perfered 2.5 gallon tank... Water change 50% 2 times a week with 100% three times a month...
Water Conditioner!!! Needed to survive! Prime is the best! Many use it in this forum!
Also you could feed him bloodworms as a treat two-three times a week! If you do get a 2.5 decorations and rocks..HE would love! But make sure they are soft so he wont rip his fins!
A stable water temp should be 72-80! Heater is needed for cool climates!
You might want to get a thermometer to monitor the water temperature. I've used the Top Fin pellets and I didn't like them because they sank to the bottom. 80 degrees would be perfect for him. Congrats on the new betta! :)