Why would a Betta fish be jumpy a week after changing its water?

Did you use Betta water treatment when you changed it. Did you acclimatize him to his water. When you change the water you drain the water into a cup (make sure the cup is deeper than the tank) with a little bit of his old water. Then, when you have refilled it with room temperature water and put water treatment in, place the cup in the water (making sure not to get any of the new water in yet). After about an thirty mins to two hours (depending on the amount of water in the glass) go ahead and dump that little fishy into his fresh, clean home. If not your betta will become agitated for a day or so; and if you don't use water treatment he will become very ill (due to the chemicals in tap water) and may even expire. if you put any kind of fish in a container to to fast it will get scared. so put the fish in the container slowly.