I've had my blue betta for a couple of months, and his activity level is not so high... it seems like he's mostly napping... I would say, about as much as my cats.
How active "should" they be?
I currently have him alone in a Hawkeye 360 view 2 gallon tank, with a 1 gallon filter running, and feeding him Aqueon Betta Pellets Betta (5-ish twice a day - I'm probably feeding him too much)
My thinking is that the 2 gallon tank isn't making him happy, because it's 2 gallons... and it's more tall then it is long... but I'm just guessing.
I'll be moving him into a 10 gallon tank soon, with a 50w water heater and add a couple of ghost shrimps and/or panda cory.