After getting a betta fish bag. You should be floating the fish bag in jar or betta tank 15-20 minute. Do it for the betta fish adapt temperature water in bag and water in betta tank. To make sure fish not shock or sick because water change. Pour betta fish and water in bag to betta tank slowly. Especially halfmoon betta because fin and tail rip easy
Beware : Plants and stone in betta tank look hard and sharp may make wound the on body of betta fish or rip the fin and tail of betta fish.
Tips : Put sea salt little in water and dry Indian almond leaves 3*3 inch of water will be good.