Why is Betta Fish Jumpy all of a sudden?

[christina]

I've had my betta fish for a month now I have him in a 3 gallon tank. I bought gravel for his tank so I took him out of his tank and put him in the pet shop cup for a water change i got the water from the water in his tank and I did a partial water change and added the gravel. all of a sudden I noticed today that he's quite jumpy which is strange cause he will usually come right up to look at me he is swimming frantically if I put my had near the tank what would cause that and how do I fix him