Hello again Chung. I do hope you try again. I can assure you this was not your fault. As for him running on the wheel in the daytime, lots of hammies, especially young ones, haven't really set up a wake/sleep pattern yet. My Ted E. Bear was a day hamster too. Every so often he switches back to the night time. Currently he is an evening hammy
. So, your little ham's wheel running may have had nothing to do with his passing. Please remember that we are here for you if you need advice. Dwarf hammies are a bit different than Syrians. They can be more cage aggressive than Syrians. Even though they are so much smaller, they still need a nice big cage. There are some additional differences in foods for dwarfs. So if that's what you come home with, let us know. It's hard to lose a hammy, especially if you are questioning whether or not you did something wrong. So, good on you for thinking about attempting it again.