If you can hear drumming from the basement fairly well when you are next to his tank, then he can "hear" it too (or FEEL it, rather). If it's loud enough that you have to raise your voice to talk over it then it might be bothersome, but if you can just barely hear it then he'll be just fine. They are used to random vibrations (i.e. your footsteps, the vacuum, rearranging furniture). Drumming should just become one of those things they ignore.
The first time I got my guitar I was playing quietly in my room (which was also my snake room at the time) and I looked over and everyone was "at attention". They were all peeping out and staring in my direction, frozen there. Then after a few days of playing more consistantly, they just ignored it completely.