My tank I got for Christmas

Pretty cool, i never like the plants on the left because they can snag a bettas fin. Are you planning to plant it later on?

agree with @zombiejessigamer on this one, usually bettas need a planted tank or a clear bottom tank to thrive and live best in... Plastic plants can easily tear their fins making it confusing to spot if its a disease or, snagging of fins...
Tank looks like it can filled up with a bit more conditioned water but its up to you, filter may run better... Also as a filter I suggest a good HOB such as any quiet flow. The one you have is more of a generic type IMO, but I don't judge lol
Most importantly and I hate that I've been saying this so often, but it was Christmas so I suspected it; Bettas cannot thrive in a tank that is less than 5 gallons or live really, they live up to 7 years (even more so) so that's like me putting you in a 6x6x6 ft room for life... also it seems your tank is uncycled which is a downside, meaning you will have toxic ammonia spikes and nitrates will go up and down causing the fish a lot of unnecessary stress..

I agree with @BettaBettas, most bettas i have kept last more than six years... Its a joke that pet stores only say they live 2-3 years max. I use tap water but i run it through a zero water filter, then let the tank cycle for 24 hours after adding new rock/plants to be sure that the water is free from contaminates. A 2.5gal tank is good for a short time, I would use it more for a quarantine tank or a nursery. Some good things to consider picking up is a water test kit, a water conditioner for betta, and a floating log or resting leaf so that he is able to literally hang out at the top of the tank. We're here if you have any questions. We would love to see you have a long and happy relationship with your gorgeous fish!