Betta Fish: First time Betta owner! Any advice appreciated :)

Sorry the photos kinda suck!! The first two photos are from just before I got my little guy. I have a 25l tank I've been cycling the tank for two months, it's planted and I do a 25% water change every two weeks. There are also an army of bladder snails that hitched a ride in on my plants but they've been helping to keep the tank clean!! I got nukey (short for nuclear bomb) yesterday and aclimitised him using the instructions the shop gave me, and he seems to be happy exploring his new home !! I use a sponge filter with the slowest air pump I could find for a decent price with an air stone to make the bubbles smaller, and there is a heater that keeps the water at around 26°c! I fed him this morning with some little Betta pellets that the shop recommended to me, but he seems to be eating them then spitting them back out repeatedly? Is this normal? I've done my research best I can, I just want him to be happy and healthy! Any tips are appreciated!