Betta Fish: Is he looking well?

First picture is him 1 week ago at the pet store and the other ones are a week later first time in his new tank, just got him today and when i was picking him up i noticed he looked a bit colourless compared to a week ago

Is it stress from the pet store? The lights? Will he brighten up within time? This is my first fish so im trying to do everything right, I acclimated him properly and have my light low to not stress him. Plenty of plants to hide and a little floating bed to rest close to surface!