About two weeks ago, I got what was called an oregon newt, but i've also heard it called a western newt or a california newt. He was totally fine, lively and swimming until i changed his water about a week later. Then for three days he sat on his rocks curled in a ball and didn't move nearly at all. Then all of a sudden he was back in the water like nothing ever happened. Then a few days later the time came to change the water again, and a day later he's back in his phase of being curled in a ball not doing anything. Is he just stressed and has to adjust again? I have a filter now, so hopefully i wont disrupt him as much again. Can anyone help?