Peanut problems

So I just moved my 7 week old mouse peanut from his old enclosure into this one because his sister really likes climbing the bars of her cage. He was previously in a 10 gallon glass aquarium but I wanted to interact with him more so I bought him a cage with bars. I put them in here about 4 hours ago and he has not tried to go to the bottom? I don't know if he's afraid of heights or maybe if I should put him in a one-story cage? Let me know what you guys think