When we humans "hear" a noise we are able to associate that noise with something, sometimes a negative. ie if we hear a siren and blinking lights behind us while driving(too fast) then we may associate that particular noise with a negative.
Likewise fish hear through the vibrations in the water and associate water movement from such with feelings. If they feel certain vibrations and a shark shows up then they will associate that with a negative next time. But if you play music and then feed them, they will associate that vibration in the water as a positive.
It's all about association, not the vibration in the water itself.
So, rock on, but don't forget to feed your fish!
In addition, a quick tap on the glass can be a negative...just like a firecracker going off to us....so don't do that. But the continual vibrations in the water...not a problem.
I can hear the Beach Boys and "Good Vibrations" and so can my fish... Oh yeah.
