How to know when agressive?

omg sorry meant to write mouse LOL

Ok I won't handle him..

It is 20 gallon glass, the front and sides are blacked out with 100% tint. Coconut hisk fiber bedding.. Plain solid black hides, water bowl, some grassy plastic stuff for heck of it... Thermostat under each hide and heat pad under the hot side, and small ceramic heater over the cool side to get the temperature up a bit. I never waited more then a few days to hold him after getting him... was too tempted to hold him cause he was so good looking lol :(