Either way here's a "spiel" about acclimation:
When you first get mr betta, float the bag in the tank.
Then after maybe 10 min, pour a small amount of tank water into the bag. Leave him for 5 min.
If he's reacting ok, put a bit more water in. If the bag fills up, pour some of the water into the sink/buckets/pants/anywhere BUT THE TANK.
Continue for 20-30 min.
Then release mr betta. If he's from somewhere else in the country (far away)
Decrease the amount of water you put in the bag, and increase the amount of time it's in there. This should allow him to adapt at a slower, more comfy rate.