The holes are made with a pen kinda thing so they arent jagged and arent big enough for him to get out of or able to make it bigger I dont think. The temps are 90 on the hot side and 80 on the cooler side with hiddy holes on both ends and the humidity is about 60%. He's only been in the tank for 3 days to cuz I made the mistake of putting a 2 1/2 foot or so snake in a 10 gallon at first. He is now in 20gallon container that has lots of stuff to take up space. I dont use any over head lighting either even though the previous owner was using that. I use an uth with a lil space between it and the tank to. What size mouse should I be feeding him if its 2 1/2 feet long?