I am a new owner of a betta fish, Oob, and I have had him for 4 days. I was going to do a water change when I noticed he is swimming around erratically, nosing the pebbles on bottom, diving up and down. The first few days he didn't do very much of this. Is he just getting comfortable, or is something wrong? I had a betta once years ago and I remember he was very calm, not like this at all. Can anyone help? Thanks!